trim questions

how have people approached this gap? i was thinking i'll just jigsaw out some more of the same 5mm ply i've been using smooth it out / glue it in with epoxy putty.





also i happen to have one of the apparently somewhat rare promasters with sliding doors on both sides. the side that's mostly blocked by the shower i kinda wanna just block entirely with more 5mm ply. question is, will it pass inspection? i've still got the other door usable and the back door kinda usable, hah.



finally, has anyone done trim repair? these shower faucet trim rings are, idk, prolly aluminum. i guess i was thinking i'd buy some similar stock aluminum and try to solder 'em up?