The pneumatic should be held closed for the hinge end glue to dry but
there should be a spacer placed just inside the exhaust hole so that
the boards do not put a sharp crease in the cloth which will accelerate
deterioration.  I believe this is mentioned in Art Reblitz's book.

Don't place the scrap piece of felt on the hinge side of the hole
but on the outer side under the elastic band; this will not introduce
a spreading action at the hinge due to leverage.

I use hot hide glue for the main three sides and PVC-E glue for the
hinge end.

Jon Page