So I've done a bunch of riding, and racing and written everything down.
Last test was to take the squish band recess right out of the head, making the squish same as the deck height, .6 mm and it did something really odd. With no other changes, the bike would no longer idle. Backing out the idle air screw, it would idle but was so rich it was burning my eyes in the shop. Until now, every other reduction in squish made it start easier and idle much more stable. At .75 squish, I could start it up cold, walk away and it would sit there and idle perfectly forever. Power was good, though no better than before and it just wasn't right down low, right off idle. So I put the stock head back on at 1.2 mm squish. Predictably, power down low was weak, much less snappy, but it did have excellent top end pull, and the spooge is back. As I reduced squish, low and midrange power got significantly better, and power seemed to change on the top end. It didn't seem to make as much power right at the very top RPM's, but it pulled so hard and so fast down low that it made it feel like it was running out of revs sooner. At the track, though, it was really fast, and I ride a high speed, natural terrain type MX track. In fact, I've never been faster on that track. Pull out of the turns was so much better. In the woods, it was incredible.
I just re-machined that (no squish band) head to give a 1 mm total for my final test, and likely run that for the fast MX. My recommendation, if you ride mostly woods with your 125/150, have that head machined down to a total squish of .8 - .9, with a maximum of 1mm. For fast MX, and general use, go 1 mm. The increase in low and midrange power, ease of starting, and idle stability are incredible.
If anybody wants me to machine their head, it's a simple procedure, and I would be happy to.