Tree Top Thrasher:

I'd paint it before covering, but not wth dope. Give it a coat of "Balsarite for Fabric," it will act as a sealer for your final sanding, (after painting the Balsarite) and help the adhesion of the fabric.

My way is to paint the firewall and the tank compartment, and sometimes on back into the radio area, with thinned epoxy for fuel proofing, and I do it before covering. That way I don't have to worry about dripping the epoxy on the covering.

And for those areas where the epoxy gets around on the outside, the places the fabric usually won't stick, with the Balsarite the fabric sticks just fine.

HTH

Bill.