Interesting yack on that mailing list from Dave Daye about different ways to glue a vinyl bag. He suggests this 3M junk, marine solvent. 5220 I think the number is. Very hard to get it off the surface. No more blowouts, maybe. DAP always seemed to give way eventually.
Brad Angus told me Paddy Keenan said he liked to find naughahide that’d been sitting in a shop window having the sun hit it for months on end. Makes it even stiffer.
Kevin
I wonder what is the difference in playing with a normal or astiffer bag?
could you tell?
carel
You might have to change the way you sit to play. 
djm
You get a faster response/more direct control with a stiff or non-stretchy bag. Some like more or less “give” as “give” provides some dampening effect for those with more spastic reaction times and muscle control, while a very unstretchy bag can be pretty unforgiving if you tend to lay on it all the time.
Royce