Hey Dale, I've done a bit of tracking, and am learning about atmonauti. not because i am ever going to be an accomplished atmo freeflyer but there is something to be thought of in regards to the body position in atmo vs tracking.
I find that the angle of flight (yah atmo you end up covering much more distance then tracking-and going a LOT FASTER :) which is what i like-faster-if you go to youtube and find freeflychild-my buddy has a video of his 1st atmo fight here at our DZ-he's flying -and made 2 points-with one of our more accomplished skydivers-you can see at the end of he video when he says 'faster, faster, faster' he leaves Ryan and flies right back to the jump run, then away to deploy-but that final section is not on the video because Ryan is taking the video (freeflychild is the one in red) and this is Ryans 1st atmo attempt so he has to deploy becore we get to see freeflychild deploy-but we do get to see him flying right back to the jump run qas ryan is deploying-covers a lot of distance and speed is easy to see once he leaves ryan at the end-its like he has turbo kicking in)
anyways, that 45% body angle seems to be a better answer for having our legs locked into the 90% angle. that angle seems to slow down tracking, and reduces the distance possible but in atmo that angle actually is helpful and increases the effectiveness of human flight. body angle to the ground is about 45% vs. tracking basically straight on belly....
which leads me to next summer working on atmo body position instead of typical tracking, and this should be allow me to fly on my back.