Vantage 400 on the truck will cover everything you can throw at it, and cover running carbons up to 8mm which is fine for gouging out welds... Thermic Lance for pins, definitely. Vantage 400 will also give enough 3 phase to run a powermax 85 for chopping up plate.
Not cheap, but a good engine drive. I have a smaller 250a multiprocess Lincoln engine drive and it's a bloody good machine.
Also, if you just want to gouge for crack removal, consider a plasma cutter with a gouging setup.
