I'm looking at a sequence of Duval . . . his wrist stays bent pretty good but he Up-Plane quicker than Lee Buck. Plus he hits it higher because he has more Tilt.
I think Duval is the best 10-2-D grip model . . . he was as good as anybody when he was winning.
If you are talking about axis tilt Lee Buck had as much as just about anyone that made a living at the game. (at least the video/photos I've seen)
__________________
"In my experience, if you stay with the essentials you WILL build a repeatable swing undoubtedly. If you can master the Imperatives you have a champion" (Vikram).
The reason you can't sustain the lag is because you are so eager to make the club move fast (a reaction to the intent of "hitting it far"). So on a full shot you throw it away too early, which doesn't happen for your short chip. (bts)