Here's a quick example with a plastic profile gauge. This one has a lock for the profile. I miss the wire one this one replaces. It's too bulky for this and the plastic 'feelers' don't align as well.
That was suggestion relative to visibility problems on bright bases where the light affected the ability to see what's happening. The pin profile gauges work better that that plastic one.Profile gauges for this are a waste of time. The tolerances you are looking it will be hidden by the profile gauges in accuracies.
Truing Bar is a lot better, even a straight cheap steel ruler is way more accurate.
One of the things is as long as edges themselves are flush with a bit of base (couple of mm), the edges themselves won't catch creating that railed ski feeling.
Remember we used to have grooves in the base of the ski, intentionally!
light bleed
I think light bleed under the true bar is the source of what most people decide is an "edge high" ski.
I buy WAY too many skis. I think in the last 20 years I've had exactly one pair that truly needed a base grind when they were brand spanking new.
But if you really wanted to see "edge high" and used a bright enough light, you could find some bleed.
Maybe I'm just lucky.