I recommend posting a sample file so people can see what you're talking about.

Anything you can do on paper you can do on a computer. You could get ten or fifteen year old scrap computers for $10 each off Craigslist (or free) and they'd work fine. Many of my programs are in the 30,000 to 100,000 line range; lots of dynamic milling. You're going to want to program like that if you want to increase efficiency, and your operator is not going to read and understand it. The only thing the operator might pay attention to is the first half dozen lines of each tool; is it the right tool, suitable feed and speed, coolant, right offsets called? Then let'er buck!

Some here have said that a dual contact Cat has some damping properties that makes it better for traditional heavy cuts than HSK. YMMV.

That would be nice. I have a routine that works for me. Hit the compressor on the way in the door, then power on the machine. Wake the computer and log in. Go back to machine and it's ready for homing, then run spindle warmup while checking emails. 4 year old Haas 15K spindle, no problems so far (knock on wood).

Yes, true position is relative.

Depends on what you want to do with it. Dual contact Cat can be pretty good and traditional hogging, but if you're going to be using that 15k to 20k range and cutting light(er) and fast go HSK.

If I'm correctly understanding what you're saying, the arcs are intentionally off center to spiral out. Sounds like that's a steel endmill? Try try using a smaller diameter solid carbide cutter with HFM strategy (full depth, small stepover, increased feed and speed.)

Yep. I remember 'cause I was working at Prototek when I made my first account.

Those are WORLDS apart. .002" true position you can hold on a Haas. .0005" you need best of the best, and if you can't afford the machine to do it you can't afford to take the job. As said before, getting the tolerance requirements as loose as possible should be the first priority, since as you're learning, tight tolerances cost money.

Is that a gluten free tax form?

If the inside floor is datum A you'll need three datum targets to define a plane. That surface will not be perfectly flat, which means you'll get different results depending on where you pick up the plane.

I use "force toolchange" to segregate operations that I want to dial in.

That's a bit big for my parts.

My post warns me if I have that situation. Your dealer or post supplier can add that function for you.

That made no sense to me whatsoever.