I would get some 16 gauge steel, and make the plate. Make a cardboard pattern for the size and holes, and transfer the pattern to the plate.
Remember, you don't want any sharp bends in the cable. A big loop is best. The cable needs to come straight from the shifter and start the loop. The cable may end up lying on the tranny/TC, I would protect it with whatever hose fits the I'd of the cable. Garden hose may work, split it from end to end and use some zip ties to hold it on.
When installing the cover on the tub I would use 1/4" bolts with a fender washer on the glass side, ( maybe 2 depending on the thickness of the washer.)
1957 WILLYS pickup,
1973 J 4000,
1978 CJ7 DD.
1979 CJ7 360, TH400/Quadratrac.
1980 CJ5 trail Jeep.
1989 YJ the CJ to YJ.