[TonyUFN]

Aren't you supposed to use the Weldon flats on your cutters when using the set screw holders? That prevents vertical movement. (Well, depending on how big the flats are and how hard you tighten, "too much" vertical movement...)

What material/flute count? That feed/speed sounds like a four-flute in steel, perhaps?

I don't use a flat. The flat is optional when ordering, but I didn't plan for using it since I figured it would shatter(as my 1/4 did) well before any other issues(slipping) occurred.
The material is 6061, the TAS are 3 flute variable.
I started off with the feeds/speeds in John's video and worked from there to get the best sounding, chip making, and fastest removal I was comfortable with.
I was hoping for fast removal rate and a decent tool life. I haven't been disappointed so far.