Shoot the crown across the grain. Be careful not to blow completely through the 5.5mm ply. Easy to over shoot.
For Clamping the underlayment with the Titebond you need to evenly apply 175 psi for max strength. Franklin adhesives is great help. Phone number on bottles.
If you can not achieve the clamping spec then use the polyurathane. It is not pressure sensitive however it is only rated at 700 psi strength. Titebond II and III is rated at 3500 psi.
When clamping layers together on a jig, use a slightly taller layers on the outside to provide an inside gully to catch the excess adhesive. The tighter the radius the longer the clamping. Max time 24 hours.
Tightbond standard sets hard with minor setback. Titebond III has longer open time and has a larger setback. Adjust jig use accodingly. Use an Armstrong S-50 notched trowel to spread the Titebond. Cartridge application with the poly.
I am offering my jig free to any one who wants to come and pick it up. I am off I-95 at the PA/DE state line. I'll also show you how to use it.
These are the shapes you can make: