milling heads for comp ratio increase

Yes that is the idead behind them and they have been out since the late 60's or early 70's and do what you say. I would surely put those in for this cam in that small engine.

BTW, when I ran the DCR numbers, I dropped the duration from 290 to 280 degrees to try to somewhat compensate for the slow ramps and get to an 'effective' DCR. So I already tried to compensate things.

But if it were me, I'd go for a different cam. My racing discipline is rally, and a real, wide torque band is critical for that, not peak HP. (That, or a 6 speed transmission!) That same approach works on for a perky street engine.