I like to use 1/4" compression bits on my PRT. Cutting speed I use is 4-4.5 IPS with at 10800 rpm. I'm sure it the bits could be faster on an alpha machine but any faster and I'm risking losing positions. I used to spin them faster but find that they last longer at a lower speed. I use 2 flute cutters on melamine and 1 flute cutters on plywood. I use a two pass system where the first pass is the full depth less .03" in the climb cut mode then the second pass in conventional direction. Dont think a PRT or PRS would be able to go faster with a 3/8" bit. The 1 flute cutter can cut faster though.