Olympic Archer Casey Kaufhold (USA) shows new archers how to determine their draw length, one of the key aspects of getting a proper fitting bow. visit HoytTarget.com for more info on Hoyt Archery's full recurve lineup HoytTarget.com
I believe, for the same holding weight, long limbs are supposed to feel smoother to draw, but short limbs generate faster flight speed for the same holding weight. Also I've read that limbs will have less weight at full draw in a longer riser. ~ 1 lb per riser inch So 40lb limbs in a 25" riser, will be 38 lb limbs in a 25" riser. So seemingly, you could get a 23" riser with long 38" limbs. :/ And it would feel the like same weight at full draw as a 27" riser with short 42" limbs. :/ They'd both look a bit weird. But this feels very unscientific and here-say, I think you really need to have access to variants you can test and see what feels good. Or just start somewhere in the middle and don't over think it.