I have been able to find this powder at Cabels (4 lbs now), and am finding it to be a reasonable substitute for some of my old standby's: A2400, Lil Gun, IMR4227, IMR4198, H110/W296.  The info on Load Data for 218 Bee, Hornet, and 7.62X39 suggests reduced pressure and/or higher velocities with good load density.  I have also used it in 32-20 and 25-20 so far with good results.  Lower pressure, higher velocities and greater load density seem to be pretty appealing for older rifles.

Anybody gone further with this powder, into some of the old large-capacity cartridges that commonly use mid-range burn rate powders: 32-40, 38-55, 45-70, 40-65 and 44-40?

I’ll offer the counter experience.

In general the powder missed its mark. Designed for 300 Blackout, it has all the worst qualities with no benefit what so ever. 
Intended for subsonic suppressed loads in auto loaders, it is a complete failure. Plenty of gas to cycle the action, that ends up in your face. Extremely loud, something completely contrary to suppressed shooting.

With low density, large bore loads, ES numbers in the triple digits are not uncommon, and the only powder I’ve seen more unburned powder left behind is Blackpowder. 

With compressed loads, it’s character changes. Becomes clean and reasonably accurate, but velocity challenged. You use 10% more powder to achieve 10% less velocity compared to 1680 in small cases like 22 Hornet, 218 Bee, even 300 Blackout. It actually excels in 300 Ham’r.

I was given a few pounds before it was released to test, and honestly have never found a good fit for it.

It is an extremely low pressure powder, with full case loads. But my experience with it in low density loads has been nothing but frustration.