I was looking for a set of block off plates when I talked to my neighbor about it. His son had just moved in and has a 3-axis CNC maching as well as the programs to cut the covers! So check out his handy work.
He's kind of floatting right now, just moved to town about 2 weeks ago so don't know what his intentions are. His father runs a cabinet shop out of a hangar and Clints been helping him out. But I think he's wanting to do this sort of thing for a living, (and work for himself.) He worked for Sky-Tec (light weight starters) for a while, but wanted to be close to family, hence the move.
Try to go through him first. Middle men are a hassle. The number listed (770-412-6403) is his fathers shop. Just ask for Clint, or leave your name, number and a brief message at the beep.....you know the drill. If you have problems, pm or email me.
When we made them, all holes were 5/16 for simplicity. So far I've not had any problems or leaks on my set. You might be able to have Clint make one hole 1/4 inch.