Sounds like you have your work cut out for yourself
We are also going thru the same situation with Inconel 718
and found reasonable results using GEENLEAF tools for a mill / turn component
Sorry we're metric but currently have cutting speeds around the 600-750 m/min range, DOC approx 1mm, feed around the 0.09mm per tooth
the 0.5" round tips are giving the best results so far
All tips don't tend to last long , everything seems around the 3-5 minutes usage, so the more you
Every consideration to having the shortest tooling, any vibration is a no-no, so consider the tip "stuffed" if the occurs
It will be a long job, but look a Greenleaf technical data - it's the best info for the machinists I've seen so far.