So by some miracle my 00s original top is in great shape, but the rear window is pretty foggy down the middle. Has anyone had any luck restoring this? I'm thinking of trying to wet sand it

 

Start with Plast-X from meguiars, maybe using it with a small electric buffer. I got a kit that provided you with a buffing tool that you use with a drill, and came with Plast-x polish and sealant.

Wetsanding sounds a bit too harsh for the condition it is in (relatively decent), I would leave that as a last resort if the milder approach doesn't work. Once you get it cleaned up keep it protected with a sealant like Menzerna Powerlock, and regular use of Plexus.

I cleaned up my Mugen Lexan window with this method and since then it remains perfect with the sealant and Plexus maintenance.

 

Clean with plexus and add a piece of carpet onto the plastic tray where it touches when you fold your top down.The carpet will prevent the dust from sticking to the hot plastic.