Tomg---Are you using Zank V-Carve Inlay procedures, or are you using the Vectric software inlay function? It seems to me that this same question came up recently, and unnecessarily, in another recent thread. I say it's unnecessary confusion because the inlay technique at the heart of this OP could be referred to via the name of its inventor, Zank, or Zank VIP, or Zank V-inlay, or Zank whatever...and everyone here would quickly know that we are talking about an inlay technique that specifically employs V-bits and Vectric's V-carve toolpaths discovered by Paul Zank (i.e., not Vectric's Inlay toolpaths!) to produce an inlaid project. It was nice to see that Beki was clear about the distinction in her tutorial.
Mike--I'd have to go back and watch Beki's tutorial again, but I think you are right. Using the original Zank specs in her multi-wood project clearly led to an unnecessarily large glue gap that showed up as a gaping cavern when she carved into the inlaid piece. You have certainly pointed out that issue with the original numbers in the Zank-Durrant white paper in the past. So, she decided to change the male specs to make the male piece fit deeper into the female engraving--0.28" start depth, I think...which is fine. And, as you would say, the difference between the female flat depth and the male start depth defines the glue gap. But, I think, she set the male flat depth to 0.02" apparently thinking that was what controlled the glue gap....if that was the thinking, it was indeed an incorrect assumption.
The project came out okay, but with only 0.02" of waste material above the surface of the female workpiece there would not have been much of a margin for removing the waste backing. Since she doesn't use a bandsaw for that, it didn't really seem to matter but it would have been a problem for the most common method of waste backing removal.
One apparent limitation on the male workpiece to keep in mind, depending on exactly what V-bits are used for Zank V-inlay work, is that the (start depth + flat depth) does need to be less than or, at most, equal to, the cutting depth of the bit. Thus, V-bits with a 1/4" cutting diameter and a correspondingly shallow cutting depth could not be used in projects where the male workpiece required large (start depth + flat depth) numbers.
As a related aside, I thought I'd return to one of my favorite Zank VIP topics: Waste-backing removal. My current favorite method, which really does depend on having about 0.1" of a gap between female surface and the male flat, is to abrade it off with an edge grinder using a cupped 36-grit carbide grinding wheel. With the 0.1" margin and a little care & attention, that bad-boy tool will grind the waste backing off of any Zank project in very short order. Obviously, with such an aggressive tool it requires some caution when you get down close to the end of the waste backing, but then one simply switches over to the usual sanding protocols to finish up. So, if your project won't fit into your bandsaw, and you don't want to take the trouble of milling off waste material with your CNC, the edge grinder (with good hand control) can make pretty short work of any waste-backing removal. Makes a hell of a lot of sawdust, too, which keeps everyone out of my shop while I'm working.