Once you choose your tool, your tool supplier will help you with specifics for that tool for speeds, feeds, and depths of cut.
I prefer "single point" thread mills because I can usually cut a wider variety of thread sizes with a single tool. With a "multi point" tool, you are locked in by both shank size and available insert sizes. 1/2"-13 takes a certain shank with one insert. 1/2"-20 takes the same shank, but a different insert. With the "single point" tool, both threads, same tool. "Single point" tools mean longer cycle times and one "single point" tool costs more than one "multi point" insert.
Contact your local/favorite tool supplier for their recommendations. If you do not have a local one, try Grainger, MSC, or Travers. Travers has the best tech support and application engineers in my opinion. The others just have sales people.