The metal back on my CTC-7 Anderson measures .05" thick. Holes are .189" dia. If I can find some large paper I'll trace the outside edges and a sampling of the hole spacing. NO way am I going to trace all those holes.
If you were closer by I'd sell you the whole set for parts very reasonable. Unfortunatly someone necked the CRT before I got it. Original owner was storing the set with the back off.