Since you’re bringing a lower-pitched whistle up to a higher pitch, and taping a hole is going the opposite direction (making something that’s too high, lower) the only way you would end up having to tape something is if you went too far in one of the steps.
There’s a reason why I listed the steps in the order I did.
Step 1, chopping the top until Holes 2, 3, and 4 are in tune to the new pitch you want, leaves the bellnote and Holes 5 and 6 too flat. So every note is either at the pitch you want, or flatter than the pitch you want. There is no possibility of requiring any tape unless you chopped too much leaving Holes 2, 3, and 4 too sharp. (It’s why I don’t just hack a big chunk off, but go slowly, cutting off a little, testing it, then cutting off a little more. It takes time to do it this way, but you end up not going too far. I do it by stages and testing rather than by following somebody else’s measurements, which might or might not work with the particular whistle I’m using, because different Generation heads play differently.)
Step 2, chopping the bottom until the bellnote is in tune to the new pitch, means that Holes 2, 3, and 4 and the bellnote are now at the new pitch but Holes 5 and 6 are too flat. Once again, every note is either at the pitch you want, or flatter than the pitch you want, and there is no possibility of anything being too sharp and needing tape, unless you chopped too much off the top or too much off the bottom.
Step 3 is carving out Holes 5 and 6 to the new pitch, leaving every note in tune to the new target pitch. Still you won’t require tape on any note, unless you carved out Hole 5 and/or 6 too much, or chopped too much off the top or bottom. With carving a hole I do it a little at a time, checking against a tuner as I go.
I purposely didn’t mention Hole 1, because it’s a special case, being responsible for two different notes. I prefer leaving Hole 1 as it is, meaning that playing open (the sharp leading tone) it’s a bit flat, but it makes a nice in-tune crossfingered flat leading tone, on most Generation whistles.
Of course different heads play differently, and the body that’s right in tune with one head might need additional tweaks when played with another head, or might not work at all, being too short or too long at the top.
As for Tommy’s instructions, I don’t know about those.