Dan:

My slow build IV-P kit came with a glass cowl so I just added 2 bid carbon for stiffness.

No problems yet.

Also aligned oil door with airflow before adding mechanical release cable accessible thru air intake.

 Regards, Bill Hogarty

P.S.  After having two of the long hinge pins break, I finally removed the cowl retaining hinges and reverted back to the screws and nutplates to mount the cowl.