Thanks guys for the nice comments.
Prairie Bowyer, 50-60 I would say is possible. IMO, the challenge is the same with longer bows but just much more challenging - keeping set down and minimizing bow stack. What I'm finding out from spending the time shooting these bows is that I'm OK with pulling as short as say...22" for shooting even though I pull 27-28". It is a different style and takes practice but it is becoming reliable with practice. A short sinew backed highly elastic bow is in my near future. Wood compression is important but I'm finding with heat treating, wood elasticity is important for the bow to have that "high quality" low stack feeling when drawing. I'm really revisiting some of the designs for the short plains/west coast designs. Enjoying a bow that is 43" ntn is making me wonder about trying for a sub 40" bow, sinew backed. Might be really fun.
Anyhow, so many things to try, what a great hobby!