I have worked pretty hard on figuring out bike/body interfaces. What I
do is adjust my seating position to one of several hand positions on
bars. I have 4 main positions on low bars, and 2 positions on aerobars
(down or up holding just elbow pads).
So when I change hand positions (quite often), I usually slightly move
seating position to some degree. It works so far, but am fine tuning
aero/low bars now. No rules because still learning and everyone's
different. But a general rule is keep elbow 90 degrees (natural work
angle standing or sitting) at any position, wrists straight
predominantly, keep knees tucked and straight as your body will allow,
foot at bottom of pedal stroke should be flat, and always have an arch
in neck which is natural on bike.
Fixed foot/pedal position is essential too which I found out. That may
be problem, but would need to see film of you riding to understand.
Maybe a good idea for you as well to see yourself riding if can figure
out how to film while riding.
Once you get the riding seat height down, its a balancing act between
seating position and hand/body position. If already have toe
clips/etc... try seating back on seat when you lower down. What ever
feels comfortable is ergonomic for the most part (within reason). And
one seating position will NOT work for every hand/body riding position:
not for me any way.