I picked up a non kite construction firewire vanguard for cheap. I was going to put launchpad deck pads on it from my shinnster but I was thinking of possibly putting a layer of 4 or 6 Oz glass underneath my feet and the pads to prevent pressure dents. Has anyone tried that before or is that a bad idea?

Go to a shaper and buy a 6 foot sheet of glass and some sun cure epoxy resin.

Sand deck and top of rails.

Glass it, put in sun.

Lightly cut/sand finish the rails where the cloth hangs over, and maybe a coat of resin over the rails if the cloth is fraying or sharp. I wouldn't bother finishing the entire deck properly because it will probably break eventually anyway.

Leave it as is. You'd wreck a decent board by slapping more glass on it.
If you learn how to ride it being light on your feet, it will last a long time.