Still, even 3.5 hrs isn't bad at all for full validation cost on this machine.
After increasing the schnorr batch somewhat and bypassing the .5TB buffering, the total maxi time to validate to 950k without sigs is 3.0 hrs (vs. 5.0 with sigs). There's still a lot of schnorr to be gained through increased pattern matching, but I don't want to burn more time on that until we have the full measure. I suspect that's about 30 minutes more of savings. I'm going to plot the comparison against a with sigs run and see if there's an inflection point at schnorr. If so that will give a better estimate of the likely outcome.