The 200DX is a good middle ground. The extra amps are not that much and you might never need them. I have not personally used the 185, but everyone I talk to likes it. Mark is a fan too, far as bang for the bucks and dead simple to work. I tend to be non-mobile on TIG and like the extra amps, I really do not use the pulse a lot. Rare I touch a pedal, but that is me.

You can always upgrade down the road as well.

Are the buildings you work at all 3 phase?