[AdamHeard]

It's an interesting topic really.

The more experienced the welder I'm talking to, the more they advocate to me that welding without post welding machining is NOT the best way to do things if you really, really want precision.

Precision is really the key. If you can design such that the warp and such doesn't cause an issue, you're golden. If not, be prepared to take a lot more effort during & after welding to straighten, tweak, thwack, etc. your frame into tolerance.