With reference to your controlling speed with Mach 3 -
I was trying to look through your Mitsubishi guide, but found it very difficult.
What external inputs will the Mitsubishi take, to control speed. - I found one bit that was very like my Omron inverter, which, unfortunately cannot be controlled directly by Mach 3. My Omron requires external switches for M3 M4 M5 - which I have rigged up with external relays driven by Mach3, but the speed control is by an external potentiometer connected to three terminals on the Omron - and is designed more for a speed control at the machine, rather than a computer controlled environment.
I have the inverter right next to the computer anyway, and can change speeds on the fly if I wish, so it is no great problem. In future I will fit an external potentiometer, driven by a servo - that Mach 3 can do.
There is another system on the Omron, where you can pre select four speeds, and select these by a signal on two wires. Mach 3 could do this very easily by a small Macro. I haven't tried this yet, because, quite frankly, I find with the Omron next to the computer, I can change to the speed I want without effort. - Although it might be different if I wanted to go away and do something else while the machine was working.