Whether a cookie cutter would see a difference in times, I don't know, perhaps depending on the diameter of the cookie. I give Brad credit for using big rounds in his tests, so the saws have to work hard.
There are compromises with any mod. A pop-up, or merely tightening the squish, increases intake duration, which may actually hurt the low end. Without a dyno, or at least a good computer model, we're just fumbling around in the dark.
However, TW does have a dyno, and he does have computer models. That's why I posted his power curve for the 460. Unlike me, TW is in a position to say whether a particular mod helps. If a pop-up didn't help, I don't think TW would do it. And what he has said about the 066/660 is that, in the old days, all you had to do was drop the squish, but with the new jugs, a pop-up is the way to go.
158 psi doesn't sound so bad, but that would only blow 135 psi where I cut.

If it were my 660, I would absolutely do a pop-up to get the compression back up.