Triathlete turned Butterflyer

Hey everyone! I've been reading these posts for months and following the great workout ideas and opinions and it has definitly helped me out! Up till before end of exams and the onset of bronchitis/cold which took me out, out of a month, I was able to fly 200y/m!!!! My athletic past...I rode track cycling, ran Xcountry, only started swimming 3 years ago but i've really took on butterfly! Last summer I joined a master's club here in Montreal and have got great tips/feedback. I'm at a point now with the fly where in training pace, for a 25m pool, I can fly around 17-20 secs as a training/fast pace and usually need 6-9 strokes. I have some tinkering to do(ie flexibility) But I am a very strong tall guy! So my question.... I have a race coming up next month and then back to school for summer(Waterloo University) where I am planning to do more races in the fall(Hopefully maybe get good enough to get on varsity team as flyer?). I hear alot abotu resistance training but one look at me and you'll think "**** he's a strong motherf***" I do have a muscled build and I think my weakness is my core strength/endurance? I am the quickest one to get excited in doing dryland...ie i used to be a gym enthusiast(I LOVE the Squat area cause of my love for cycling) But now I'm totally focused as a flyer(well on the side I'm training for a 1:30 half marathon hehehe). Anyway with all that out...I was wondering the following things: -> I can manage 15-20km a week consistantly for my training. I do IM/Freestyle and looking to hit up a open course longdistance freestyle swim for endurance(I've done Half Ironmans during 2nd year of university hehe). How much % should my fly take up if I am looking to specialize in it?? I know question is...50,100,200??? Err I am better suited cause of my power for the 50 and 100 but I have done half ironmans, full marathons and stuff. I do that IM/freestyle of course for conditioning. -> What dryland stuff can I do to improve my overall conditioning for the fly specifically? When I say I am strong...well I can easily do FULL-MAN chinups/dips with additional weight and I beg for more :P -> I'm currently working on fly drills/core everyday. I've only recovered from Bronchitis...is this a good approach? I could ask my masters coach but he/she is not a fly specialist and I can't attend this term to most practises cause of schedule but I have time outside of it? Any ideas or suggestions would be great and awesome!! And I'm totally excited I am finally part of this community!!! -Eager and Excited Fly newbie