Vintage Pt-19 Question

I just acquired  an older Pt-19 that is in pretty good shape but is missing the firewall.  It is an older plane with blue wing and yellow fuselage.  The firewall should be blue and I found one but does anyone know what size screws to use to attach the .049 to the firewall?   Here is a internet picture of firewall set up I have.

The screws in your photo look factory correct for Baby Bee to me.

I’m sorry that is a picture I found online to show the type of firewall I have.

I can't say for sure.. but I would personally try to source some small (#4???) sheet-metal screws that are at least 1/2" long. The screws need to pass cleanly through the four mounting-holes in a Cox .049 Babe Bee engine without binding... but also need to "bite" into the plastic firewall to tighten the engine securely.

Screws of that size aren't easy to find. Some screws that are used to fasten "name-plates" onto plaques/trophies might work..

I am unfamiliar with the vintage model, so be careful with fitting the screws. My PT-19 is the later version that has a product-engine.. rather than the Babe Bee.