Seat, mounting bracket, and pedestal repair and/or replacement

[soulseller]

My V came with 2 Todd Freeport 200's that are probably salvageable with a little bit of work. The problem is that the mounting plate and sliders on one of them is completely broken and is currently hanging on with some ductape and bubblegum, the other one is not too far behind...

My big question is that the pedestal on the captains side chair is loose, I tried tightening the screws but they just spin freely, I tried taking them out, but again they just spin. I'm assuming there are nuts on the backside but as far as I can tell the underside is completely inaccessable, any suggestions on how to remedy this issue?