Spar countersink templates

I?m getting ready to begin countersinking my RV14 wing spar. There seems to be a consensus that templates are the way to go.
Can someone tell me what is the approximate gauge thickness for the templates?
I think it?s .063.
Much obliged / jt

I used scrap angle and match drilled a few holes so I could have it behind the hole I was countersinking. The spacing changes along the length so I just made more holes in my angle as needed. I just used cheap scrap HD angle.

I didn’t try to have a long backer. Just moved the angle as I went.

Use a piece of steel. Thickness doesn't matter much. I think I used 1/8 inch mild steel I had laying around. I tired aluminum but the hole enlarged after a while. You dont need a jig, just a piece of steel with a hole in it. Just move it one hole at a time. This just prevents the countersink from moving off center as you countersink it

The tank attach screw countersinks?
No jigs required. Rivet on the nutplates first. They become the jig.