Pacing for 5K Postal Swim

Hi All, I'm going to be doing the 5K Postal Swim in about 3 weeks, and I need some advice about pacing. A little background: I'm kind of a newbie. Last year, I participated in a bunch of open water races, but my focus was on participation rather than racing. I did some long distances, (1K, 2K and 4K events with a few minutes rest in between), but I didn't have any goals related to speed. This year, I've been focusing on speed. My coach told me to stick to short events (except for postal swims). So far, I've done three races this year (all 1K OW), and I've treated them like races. I want to do the 5K Postal Swim, but it's just an extra little adventure, not a main event for me. As such, I haven't really been training for it. I swim my normal 3,000 yards per day (7x per week), and add in a longer distance (usually 4,000 yards) when I have time as long as it doesn't interfere with my other training goals. In the next two weeks, I'll do a 4,500 yard and a 5,000 yard practice. I rarely do long distance time trials in the pool, so I don't have good data about how fast I should expect to be able to swim 5K. My 1-Hour Postal Swim pace from January was 1:52/100 yards (2:02/100m). This week, I did a near-race-pace 1000 yards in the pool at a 1:47 pace (1:56/100m) I should be able to hold my 1 hour postal swim pace (1:52/2:02) for the 5K. The speed gains I've made since January should make up for the extra distance and the long-course pool. I actually think/hope I should be able to come in a little faster than that. So, I know of two ways to manage this: Go by feel. Start out easy and build intensity after each 1,000m. Go by the clock. Hold myself to 1:52/2:02 for the first 3-4K and then give whatever I have left for remaining distance. What do you guys think? Katie