Manny: I had been going thru the same glue debate that you are experiencing right now.
I went with hide glue for two reasons:
1. chemistry- after doing some sinew patch/wraps on some limbs I can see that the hide glue/sinew combination becomes a single entity. The mixture of sinew and hide glue will shrink as a single unit. It is strong as h*#*!
TBIII and sinew just can't do that. The TB is just doing a good job of sticking the sinew to the bow.
2. reading Jay Massey. If that guy could hunt Alaska with a sinew backed bow (hide glue) then there is no reason for me not to use it. Put on a good finish (I like your spar urethane idea) and go with it.
I'd vote for the short bow to get the most benefit from the sinew.
The way you spit bows out I wouldn't worry about it. You could sinew/hide glue a couple and sinew/TB a few more all by the first of August!