Lots of good suggestions above.
My preference is 2D Adaptive Clearing with a finishing 2D contour profile. Adaptive Clearing is designed to keep a constant chipload (horsepower requirement) and is great at maximizing the smaller machines. You can also add pre-drilled holes in HSM so that you aren't always boring with the end mill.
I would try to take a more agressive cut on the PCNC770. I am not an expert, but I would plug in 6500 RPM, 0.2" WoC, 0.250" DoC, and 0.003 IPT to see what feed rates you can get (it should be around 39 IPM). CAUTION: Remember horsepower isn't calculated in HSM. I think this
calculator and this
reference site are a good starting point. Based on those calculators, it is right around 0.95 HP assuming an 80% machine efficiency. it is worth taking a few test cuts starting at 60-75% feed rate (of 39 IPM).
If you have a spindle meter or ammeter, see what the spindle load is during the cuts. It may be counter-intuitive, but you want to take a more aggressive cut. Aluminum is very forgiving, but in general too low of feed will serve to dull the cutting bit since it is work hardening the surface and not removing material quick enough.
We bought some Lakeshore Carbide 1/4" 3-flute ZrN coated roughing/finishing end mills to use on our Taig CNC mill. They are a work of art and I am anxious to test them out.
Are you aware you can also get HSMWorks as well? This would only be useful if you needed 3D profiling (maybe some awards or making molds for casting urethane??).
Are you planning to press-fit the bearings? If so, I would do a 1.124" hole.
Enjoy the machine and be sure to share some photos of what you make on it
