Can you source screws from another saw that screw into plastic that have higher raised threads so it cuts into fresh plastic when screwed in? even if they are too long you can cut them down and put lock tite on them, use the red version so it bonds stronger. If you have a friend that works at a body shop ask them to help you with providing some 3m tpo plastic parts repair (70 bucks for 350ml) and you pay for a replacement mixing nozzle...that stuff is the cats meow for permanent plastic repairs ..inject it into the holes and immediately screw the screws in but not fully tight, let sit 5 minutes and remove the screw and remove excess immediately, 1 hour wait and you can fully tighten them down and use blue lock tite and sand off any excess. If choosing to use a epoxy I would suggest getting and using bob smith brand quick cure, its got a nice and thick consistency yet should be able to drip it into the hole using a bamboo skewer, fully hardens in 10 minutes after it cools.