Use the most-recent plug-in from the PMDX web site.
As for which profile to use - that depends. When you install the PMDX plug-in, it will install a couple of sample profiles. I don't recall their exact names, but they start with "PMDX". I think one is for the PMX-424 specifically and one is for the rest of the PMDX devices. If you are running a mill, then use one of this as a starting point. The PMDX sample profiles have the plug-in already enabled and some basic settings pre-configured. You will still have to set the actual motor parameters (steps/inch or steps/mm, acceleration, max speed), but the sample profiles have settings that should move your motors, even if not a calibrated distance.
But make a copy of the profile before you start changing anything. In the Mach4 loader, click on the profile name and then click on "copy profile". Name it whatever you want. Then open that NEW profile that you just created. This way, installing an updated PMDX plug-in won't overwrite your working profile. Note that up through the most recent plug-in, installing (or re-installing) any version of the plug-in does NOT overwrite the sample profiles. But they may change their minds about that in the future.
