I got the 1/16th in by ½ in copper flat bar for the buss bars. The 1/2in is too wide, so I trimmed off 1/8 of an inch to 3/8ths in wide. (bottom strips) I drilled the holes accordingly and put them in. One thing of note is the screws that come with the circuit breakers are too short to have enough thread engagement through the buss bar. I had to order screws that are just a tiny bit longer.
