Trevor and I measure these things differently, and have different targets as a result. I strongly suspect that we are doing pretty much the same things, but just talking about them differently. So:
I test mine the way Fred Dickens taught me to: by tapping on the top and back with the hole (more or less) plugged. This (more or less) cuts down the coupling between the top and back, and gives you some semblance of their actual resonant pitches (more or less).
The closer the 'real' top and back resonant pitches (which you cannot actually see in the assembled box) are to each other, the more strongly they will couple. This will have the greatest effect on the pitch and activity of the 'main air' and 'main top' modes. As usual, you're looking for a balance here; too much invites 'wolf' problems, but you do want strong coupling: I find a semitone difference is about as close as I want. You also have to consider what happens when you string it up and play the guitar in. On very lightly built guitars the stress of stringing can drop the 'main top' pitch and raise the 'main back'. Basically, the back is being 'stretched' by the neck rotation, which acts on it like tightening a drum head, and the top is undergoing the opposite stress. Tis is not a big thing on most guitars, but sometimes... On my guitars I typically find that a month's worth of playing will 'loosen up' the top enough to drop the 'main top 'pitch by about half a semitone. Also, of course, if you're doing your tap tests on a box with no bridge, you have to think about what will happen when you glue on that massive brace. On my guitars, the 'top' pitch usually drops by about 1/2 semitone; YMMV.
So, all things considered, if the assembled box with no bridge has the 'top' and 'back' tap tones at the same pitch when the hole is blocked, I figure I'm in the right range. I don't want to see the top higher in pitch by very much, since almost everything I do is going to drop that pitch, and I'm trying to avoid an exact match. Still if the top pitch is only 1/2 semitone below the back with the bridge on, I expect to get a little 'bark' in the low range (typically at G on the low E string) at first, which plays out relatively quickly. This is a good time to think about bridge mass.
Again, Trevor holds and taps his guitars differently, and that could account for some difference in the result. Also, he's making his sound, and I'm making mine. We might like different things, and who's to say which is 'better'? If you're following his system, though, you should try for his numbers, especially the first time.