USRPT training - how should I identify goal time?

Agree with getting a coach and/or some stroke training before diving into the USRPT. You'll wind up with an injury if your stroke isn't right. And USRPT isn't a good training regimen for distance training, IMO, it's for pure speed. Distance training is more about holding a constant, sustained pace for a long period. It's mental as much as it is physical, so doing short pace work all the time isn't going to help you as much as you think it might. Take a look at the sets that Coach Emily puts other there for endurance to train for the longer distances. She has a great mix of speed and pacing.

By the way, another thing to do for distance swimming to help break the monotony and to give good feedback is the Davis Mile. 11 laps, rest :10, 10 laps, rest :10, 9 rest :10.......down to 1 lap. Look up it. You can print out what the splits should be for each leg, and get some instant feedback by comparing your pace against your theoretical splits. Now that one is set up for SCY as per typical US pool, so you'll be at 1650, rather than 1500 meters, but given you are targeting 3000, I figure that is probably better than starting at 10 and getting in only 1375.

That 2:05 / 100 m was a thing in the past, and I'm most likely currently at around 2:00 / 100 m for 1500 m now. However, the coach has noticed me that my technique is actually better when I'm swimming faster, let's say, 1:50 / 100 m, if I can make it, but it is clearly unsustainable. (1:40 / 100 m is my all out speed for a single 100 m). Also, when I count strokes per length, my all out count is even sometimes less as my sustainable count. When I go all out in a 50 m pool, I can cross out in around 50 strokes at 45 seconds without diving, while if I'm going to swim 1500 m in the same pool, the spl in the latter half eventually becomes about 57 - 60, further confirming the fact that my technique eventually breaks down when I'm swimming long. If I am struggling thru a traditional set, I feel I'm forcing myself to swim with bad technique if I get tired, which I tried once last Saturday after a gym session on Friday evening, and felt my shoulder afterwards (most likely because I resorted to bad technique to force myself thru the set). However, in USRPT, anything less than the best possible form for me will eventually lead to failure, causing me to stop the set. If you're not going to ever entertain anyone else's advice that contradicts your preconceived notions, why do you continue to ask questions?

DISCLAIMER: I am not a true believer in the pure USRPT form of training. I think USRPT is going to be harder to translate to a distance event or open water swim. Also if I remember correctly, USPRT is mostly 25s and 50s at pace, not 100s (although my training partner, Trip, loves to do 100s USRPT!). As for identifying a goal time, I wouldn't constrain yourself based on a pace you held in practice. Think about what you would REALLY like to (realistically) go, and set that as your time.

I still do not think someone of your ability level should be trying to pound out 30x100 :20 RI at race pace, especially not on a regular basis.

I agree that good technique is paramount, but keeping motivated is also important. Generally for USRPT one sets their goal time based on their goal for swimming in a race. You seem to have set it based on extrapolations from a timed 1500. This is going to be closer to giving you a VOmax time than a USRPT time. Building your speed before building your endurance is certainly backwards by conventional wisdom, but also certainly USRPT builds endurance. If you want to focus on speed then focus on speed. I'd suggest setting a 200 goal time, divide that by 4 and take that as your goal time, then 20 sec rest and go again. Rushall says not to worry about failure in the first 5 as your body is getting used to the work. If your first failure then is at 6, fine, failure leads to adaptation. Will this help you 1500, absolutely(as long as technique improves.) As Dave Salo says"all my swimmers are sprinters, the 1500 is just a long sprint". Granted his swimmers are elite, but having the ability to "get into a higher gear" is useful.

Have you also tried doing 50’s, even 25’s? Like at a pace that can be held for 5 -7 repeats before needing to skip one. Your average pace would be faster than if they were with 100’s.

I think you would do well to improve your stamina before jumping into that kind of interval training. Not sure where you are getting your workouts from, but if you like the idea of more, shorter intervals, go back a couple fo years on the Basic Training forum, and check out some of Mark's workouts. An example is that tomorrow, the main set I'll be doing is 40 50's at 500 pace with 20 seconds rest. For him, that is :33, or :53 intervals. I'll modify it to :37/:57 because last time I tried it, I was shooting for :39's, and was coming in a couple of seconds faster on every rep.

What will happen if I try to do it twice a week? USRPT is the training method which can give me the most motivation because I can see if I can get improvement literally every session, like playing computer games. USRPT encourages me to push my limit, while traditional training teaches me pacing well, and now my main focus is speed over anything else. I think you should do it zero times a week. If I remember correctly, you say you are in your 20s, and want to hold 2:05/100 pace. That tells me you most likely have some work to do in your stroke technique. Gutting out a bunch of "race pace" 100s is a perfect way to reinforce bad habits, which should be the exact opposite of what you want to do, motivational or not.

I think you should do it zero times a week. If I remember correctly, you say you are in your 20s, and want to hold 2:05/100 pace. That tells me you most likely have some work to do in your stroke technique. Gutting out a bunch of "race pace" 100s is a perfect way to reinforce bad habits, which should be the exact opposite of what you want to do, motivational or not. That 2:05 / 100 m was a thing in the past, and I'm most likely currently at around 2:00 / 100 m for 1500 m now. However, the coach has noticed me that my technique is actually better when I'm swimming faster, let's say, 1:50 / 100 m, if I can make it, but it is clearly unsustainable. (1:40 / 100 m is my all out speed for a single 100 m). Also, when I count strokes per length, my all out count is even sometimes less as my sustainable count. When I go all out in a 50 m pool, I can cross out in around 50 strokes at 45 seconds without diving, while if I'm going to swim 1500 m in the same pool, the spl in the latter half eventually becomes about 57 - 60, further confirming the fact that my technique eventually breaks down when I'm swimming long. If I am struggling thru a traditional set, I feel I'm forcing myself to swim with bad technique if I get tired, which I tried once last Saturday after a gym session on Friday evening, and felt my shoulder afterwards (most likely because I resorted to bad technique to force myself thru the set). However, in USRPT, anything less than the best possible form for me will eventually lead to failure, causing me to stop the set.