Out of the seven charge weights from minimum to maximum, three were under 0.20", with one almost breaking 0.10". Largest group size was 0.67". It looks like I have a decent OCW-type vertical consistency for 0.5-0.75 grains around the top end.
Now I'm going be stuck paying $40/pound for powder.

I still have a couple of other powders I'd like to try under those BlitzKings, but I have a feeling that N540 is going to be my go-to powder.