I would try wire pulling gel or water before I put other material into the suppressor.
If I was going to put other stuff into it make sure it doesn't/can't move around. Maybe a thin layer of spray foam insulation. I would worry about some of the metal you're talking about moving around and possibly causing a bullet strike.
Sounds like you're in a place where it's easy to buy so I think I would do the gel and if that didn't work I would buy a better one :-)
A different host or ammo may also be quieter and worth thinking about.
He who dares wins.
NRA Life Benefactor Member