Personally I use the calliper arms to get close, and the noise of the rim touching them. The white patch on the calliper arm is helpful to see the gaps. Once I am close I put the dial indicators on and I find them a great aid, especially for even spoke tension, it allows you to watch the rim move, keeping an eye on both lateral and radial at the same time.

It all depends what you are after, I like the challenge of getting as close as I can (we are all on the spectrum, just depends whereabouts….lol), again and again….I build wheels for fun and friends, when I retire it will be for friends of friends as well!

Build a wheel to do a job, that’s cool, but I have to satisfy something in me while I do it. You choose why you do it.