Good post D-
Couple points of clarification...
1) I like .011-.013 on the intake
2) If you're in a pinch and cannot get the right bucket, the buckets are hardened all the way through... You can actually mill, file, sand, etc the bucket within reason- just do your best to have a square product when finished. (I hate typing tricks like this as I'll probably get chastised by someone that doesn't understand the system, but oh well
. Take the suggestion at your own risk. Your milage my vary
). I've done this on my own car and works just fine. When you're setting the head up on the bench, most builders simply tip the valves to work with a bespoke bucket for that location, as it's just not practical to have adequate inventory of every single bucket available (there's a LOT of them and they're pricey little guys).
3) Point of clarification on the flat tappet system in an old push rod engine from what we have... Flat tappet lifters are a much different system than our wiper system and the lash measurements are not really comparable. Flat tappets are actually dome shaped and spin against the angled cam lobe which forces the tappet to spin. There's little "wiping" action that occurs at the tappet to cam lobe interface on a flat tapper pushrod engine. On the other hand, our "big cam" is truly a wiper- there's no spinning and it needs more lash by comparison...
4) There may be more issues to the 2ZZ cam system that lash cannot fix, FWIW... Could be bad hardening on the intake cam or rocker surface, or some combination of the two. However, increasing the lash seems to solve the problem and it's the only commonality I've found so far between those that wipe cams and those that don't...