Sheet metal rear side windows...

Hey guys and gals, I was pulling the carpet and side panels out of the cargo area of the xj the other day. While I was doing so the idea popped into my head. Why not take out the glass and sheet metal in the holes. Now I thought of two ways to do this...
1. cut exact fit pieces and weld them in place (permanent)
2. cut pieces seal them with windshield glue and rivet then in place (semi permanent)

A few questions...
1. Should I use heavier gauge sheet metal or same as the xj
2. Should I incorporate ribs to reduce the wobble
3. If I do the semi perm should I leave a tiny gap to allow for flex

Your thoughts and tips would be very helpful

why not use perspex...that side window is kinda good to see outta what ya doing why wheeling..............

I have seen a 2 door converted to a panel truck to haul parts for a small dealership that sells foreign car parts. It looked great. They put sheetmetal over the rear windows and painted the whole truck a sick green which was their company color.