@adbuch- thanks.
The air is actually dryer than my previous 'little boy' Kobalt 4.5cfm unit because this new one has the Motor Guard 60 final filter, which also traps any residual moisture that may get through the 1 Qt. desiccant dryer. The sight glass on the desiccant dryer is not too reliable of an indicator. Its easy to check the MG filter though, so I've been doing that weekly if not daily during high use. After >4 hours of compressor runtime, so far so good on MG filter, still like new, no moisture that I can feel at all, and clean; more smudges from my grubby hands than from air flow.
I still have not re-setup the PMX65 beast and torch for more testing. Reason is- busy with jobs/projects but also because when plasma cutting with the PrimeWeld Cut60 and UPM105 torch, I'm getting absolute square edges, no appreciable dross bottom or top, and 100% continuous cutting at 45amps. Have cut 16ga, 14, 12, and 10ga HR with all perfect results. 12gaSS with equal or less dross as I got previously, with is slightly more than HR but not bad, easy cleanup. Net: the system is working great, I'm not anxious to change it.
I acquired the PMX65 because it was pre-Sync gen and used one time, and for a great price. And I thought cutting 3x faster would be nice to have. I failed to anticipate the domino effect of having a CNC machine with high mechanical resonance (due to high center of gravity and insufficient stiffening components). To compensate for the mech resonance, I reduce acceleration config to a mere 400mm/sec2. This then translates into long deceleration distances when cornering and stopping when running at such high speeds as the PMX65 is optimized to cut at, which sets up the condition for more dross bottom side at corners than I care to tolerate and clean up. And previously, I was not able to dial in the lower amps and slower cut speed with the unit, even for the few cuts where I had the sufficient air flow and pressure before tank and compressor capacity expired.
Some good new/tips to pass along in this journey...
I built another of the HF dry air supply systems as pictured for a buddy just last week. Rather than use the copper tube w ball valve water collector, I tried a Milton water/filter trap ($50 amazon) rated for 250psi in place of it and it worked great, trapping nearly all moisture condensed up stream, leaving the tank empty of most residual water from the former condenser/trap. That's a net zero $ since the copper sweat fittings and ball valve are getting expensive these days. I also built the second unit with a soft copper tubing (as for flare fittings) as the condenser, 6 passes 14" long. Works great, savings of $60 over the purchased transmission cooler tube and fin unit, and another $50 in saved sweat fittings for the rigid copper tubing alternative.
Second- I read recently about ceramic anit-spatter spray for MIG welding tips/nozzles, but the brand recommended- Loctite, is $60/can. I had some CRC brand Dry Moly Lube spray from another project so decided to give it a try the other day on my plasma nozzle tip and mach shield. WOW! after 500 starts cutting 10gaHR, 45 mins of cutting, the nozzle and orifice still look new! No appreciable soot, spatter stick, or wear. Amazing.
Third- improved my gcode for the torch touch-off cycle. read about it here-
https://forum.sheetcam.com/t/reverse-pr ... h-off/8114 . This improvement, one line of gcode, virtually eliminates the effect of flex on smaller gauge metal such as 16 - 12ga. when running the torch touch-off cycle with a probe limit switch. Would work for ohmic too but likely not needed unless that method has consistently poor electrical contact.
As for the future of the PMX65 on my current machine, it's down the list of priorities for now, but keeping it for another CNC someday expecting it may be able to handle the BEAST.
Thank you all for your help in sorting things out the past several months.
Having a big anvil you can work out any frustrations you come across. 
