help with upper molding installation

[rmmchl]

a lot of my holes are stripped and the screws need to be small enough to go into the countersink, or they affect the vinyl strip that slides into the molding. A pop rivet gun will not go between the small channels on the molding, so that is not an option. some of the holes are 5/32 now-a few are 3/16-------------- some  can be screwed by the 8 x 1/2 flat phillips, that seem to be correct. But I don't know what to do to fasten the stripped out ones. Does anyone have any help on this matter?

[Larry & Norma]

I replaced some with stainless steel countersunk machine screws/washers with nyloc nuts, 4mm if I remember correctly.