New kid on the block - Mesa driven plasma CNC.

Gents!

Starting new topic as I don't want to do off topics somewhere else. The time has come to make some metal parts using tools I already have. During annual review of my "weird boxes" (as my wife use to called them) I found some Mesa cards, old Dell Optiplex PC, some servos, Stahlwerk CUT 70P plasma cutter. I think it is enough to say that probably a new CNC plasma cutting machine will emerge from it after 9 months.

Initial assumptions:
- 150 cm x 100 cm work area
- light construction
- belt drive (HTD-3M 20 mm or 25 mm wide)
- Linunxcnc on board
- THC internally in Linuxcnc

My biggest interest is cutting light gauge mild steel and stainless: 0.6 mm (GA 24) to 3.0 (GA 11). Occasionally chunks like 20 mm. 
My understanding is that the lower amperage setting of plasma cutter will force me to increase cutting speed the thinner sheet i will cut. Thus machine gantry and Z-axis assembly weight must be as weight efficient as possible yet still. For drive side - i have a bunch of AC servos - some are chinese 180W integrated AC servos (reguire 48 VDC PSU), some are chinese AC servopacks (230 VAC power) 400W, 600W and 750W. I found some Electrocraft E240 DC permanent magnets servos as well, together with UHU drives (some grandpas probably still remember what UHU servo is:D:D).
Not to waste resources (those servos will be assigned to various projects) i plan to use one drive for Y axis (gantry) - mechanically coupling both sides of the gantry and use HTD 3M 20 (25) mm belts for drive. There is pros and cons - i'm aware of it. Wanna try. After all - it is home shop fun project.
There is two main concers here:
1) THC (i'm not smoking)
2) plasma source
3) Mesa cards

1) I have no Mesa THCAD among my Mesa boards, so the question here is: is there other way or I have to find a way how to finance it (my budget is already gone). How accurate voltage measurement must be for Linuxcnc to perform THC well? I know some of you will say "not worth to reinvent the circle". At some places 1 USD means waaay more then in other places. In my place i need to add sadistic taxes, import fees, customs, freight and VAT on top of every oversea purchase. And i like thinkering:) 

2) My plasma source - Stahlwerk CUT 70P is, unfortunately, HF/HV arc start type. After reading here and there this is the easiest way to get frustrated during first trial and error cutting. I have a change to ruin my budget even more by buying almost new Hypertherm Powermax 45 XP. Unfortunately with no CPC port and with handheld torch. Machine torch price is more than my Stahlwerk CUT 70P brand new with 7 years warranty! (Are they crazy in Hypertherm?!). Anyway I can get 45XP for USD 1000. The rest of the machine I will make out of logs and branches from nearby forest - no problem:)

What you think about plasma source choice? If i go with 45XP I'll have to stick to handheld torch and do some mods due to the lack of CPC port. Is it doable to mod 45XP? Where to get ArcOK signal from? 

3) I have the following Mesa cards: 7i85S, 7i76D (i think two pieces) sinking, 7i96S (i think still two pieces) and 7i92TF (i think still two pieces). What would be the best pick for my machine? Keep in mind I'm planning to make CNC router and CNC conversion on lathe and milling machine out of those cards...

Thank you for your inputs and constructive criticism:)

I really think becasue your budget is blown already you should buy the 45XP and purchase a CPC CNC interface for it from Hypertherm. I'd also buy the Connector cable they  have although you can just buy the plug and make yor own cable. Then If you get that far. you might as well buy the THCAD2 from Mesa. (If you are in Australia, I might have a THCAD-10 here I could part with.)

PLasma is not an entry level sport in my experience

Thanks, Rod for your input. I guess i'll buy THCAD. CPC is hard to swallow. Simply expensive. Any options to get usable signals from machine internals in other way?
ArcOk should be easile obtainable from PCB, controls from Linux via relays to start plasma should be easy. THCAD-300 straight from the torch connector should be fine as well, isn't it?