One thing about truing on a vintage bike.. My old frame isn't quite perfectly aligned. I'll have to deal with that someday, but until then, it doesn't hurt to build the wheel for the bike

I've always trued in the past with a homebuilt stand, and using a pen or something held by one hand as a single point reference point.

Anyway, I tend to have troubles paying attention to both hop and wobble at the same time. One nice thing about the gauges is that one can choose a few spokes to adjust, say for right/left wobble, then quickly look at the other gauge to see if one should tighten/loosen, or just tighten, or just loosen. And thus adjusting both wobble and hop at the same time. At least I find it to be convenient. I need to add pinging into my routine too.

I haven't tried one of the Park stands to compare.

The VAR stand is easy to adjust for different wheels, but is not automatically self-centering, although I presume it could be marked and calibrated if one had certain wheels to true. But, yes, if one was doing say a dozen identical wheels, one could adjust it and center it, then blow through the wheels without checking dishing, or only doing a wheel flip at the end to double-check.

I have an old VAR truing stand, but I rarely use it, except sometimes when first building a wheel from scratch.

For me, the best wheel truing fixture is my bike fork or stays, with the brake pads as guides for both radial and lateral deviations.

No problem -- flip the wheel around in the fork or the stays and make sure the rim position doesn't move. I have also centered rims over hubs by looking through the valve hole at the oil cap in the center of the hub.

The point was that things like the brakes work best if the wheel is centered under the calipers. So, truing/dishing to the frame isn't always a bad thing.

A millimeter or two plus or minus may not be a problem. Most frames IMPE are out by that much. But more than that and your rear wheel might not follow the front, making handling a little interesting, especially when you go fast. Why not just straighten the frame?

As far as centering by looking down the valve hole, I don't see how that can be accurate to less than a few mm, if that, and only on the front wheel. That seems more like a "make-do" solution that will get you by until you can use the right tool.

Forgive me for sounding like a snob but I've been a mechanic so long I guess I've forgotten what it's like not to have the right tools and techniques. So, Respect. I admire your can-do attitudes, even if I'm not exactly confident in your workarounds.
I guess if you're building wheels only for yourself, I guess it's one thing. But if you're building for others, that's another. I talked to a mechanic once BITD who told me he would "eyeball dish" (exact quote.) I asked if he flipped the wheel in the stand and he said no. I don't know what technique he used, but I kinda lost respect for him after that.

I've got a Park and a Minura from 30 years ago. I use my brake blocks when the bike is in the stand.

It's great to watch a perfectionist take his sweet time, using dial gauges on an old cast iron stand (C&V content) to make a wheel effin' perfect for the right bike. Up, down, side, tension, pull the wheel and stress it, gauge it, touch it up. Inspirational. Second only to the frame build itself.

Lesser bike wheel builds can use brake blocks, tie wraps and thumbnails with satisfying results as well.

I do the same thing, only I use a ruler and some rubber bands. Get the ruler centered in the frame (or fork), and you can get your dish set, and if you slide it down until it almost touches the wheels, you can get the wheel round. I've built at least 3 sets of wheels this way. I have a dish gauge, but not a wheel truing stand. I use the dish gauge as a double check that the frame isn't tweaked.

Nice! Good thinking.

I loves me a good McGyver.

One thing I like about real truing stands is the steel calipers that scrape against the rim. I true by sound as well as sight.

me as well.

I only use those for CFRP rims. I like to hear metal rims when I'm truing.