You are going to have to do a lot more reading about what HSM is, because the questions you are asking are very "traditional machining" oriented and are not really what HSM is about.
Modern Machine Shop online has had several articles about high speed machining and how to get started in it, I suggest searching for those articles and anything else you can find.
Depth of cut, RPM, stepover, et cetera are all related to what your specific machine wants to do, not necessarily what the cutter or the material would like to do. So some planned experimentation is necessary to get HSM up and going on a machine.
The Machinist's Chatroom
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