Looks like a foldable topper?
If so, I would:
1. Cut a piece of 1/4" ply the exact size/shape of the topper (including the seam cut.)
2. Glue and staple it to the bottom of the topper (covering the chip wells)
3. Flip it over and fill in the wells with the appropriate thickness wood to be flush with the felt.
4. Spray super 77 spray on existing felt, wait until tacky. Recover with SSC, wrapping around the edges and stapling to the bottom.
I would want to add padding, but not sure how it would stand up to folding. If you are ok with not folding for storage, just add the 1/4" ply to the top, then glue on some volara for the playing surface pad, then add the SSC.
Yes, that would remove the trays (I'm not a fan of them.)
If you are keeping the trays, just cover with the SSC as if the trays weren't there, then cut them out after you get it good and tight on the surface. Start with an "X" cut about an inch in from each corner of the tray, and wrap them under and staple. I'm assuming there is some plastic chip tray that goes in there?
Measure across, add around 4". That's how much cloth you need. Make sure your SSC is wide enough. Typically it is sold by the yard (3 feet). You will probably need 2 yards. Bit don't take my word for it, measure and see.