I like using dials, but as I get better at building, I find myself using straight edges for references more often. (IMO straight edges are easier to use than either dials or calipers.) I still measure every wheel I do and keep a record, just because I'm not really sure how strong and stable my wheels actually are. I do a whole quality control program on every wheel I build, and occasionally re-measure to see if the wheels is stable. After I build a couple of hundred wheels, I'll relax a little, and put away the dials. At my current rate of production, that will take about 150 years.
I have Racelite manual that says 10 thousands (0.4 mm) is the tolerance, and I find that pretty easy to get with new rims. When I get that close I switch to balancing tension. I doubt many production wheels are that true and round.
My homemade tools work better for me than Park stuff, but they probably require too much set up time and look too klugie for a pro shop.

em