Boy O Boy, Just take your pick ENE MENE MINe MO Witch should you choose. I've cut plenty of alum molds never 6061 unless it was a vacuum form mold, mostly injection molds. We would rough with a 3flt Iscar .750 dia. .125 deep 250 ipm 4000 rpm with air blow. Make sure chips are flying. Finish with your ball cutter use flood. Have fun and play with your feeds, every machine has its own sweet spot, (feed,rpm,holder,spindle,fixture,control) are all factors in high feed rates.

I'll make it simple, you got to try it. But before you do, gather all your parts and pick one part you like to use.Let the vendor lay it out on their system then and let them show you the pro's. And I mean PRO'S. It saves use machine time may be alittle more engineering to lay out multiple parts. Have fun challenge the vendor.