They are about 15 places apart on the burn chart, with H1000 being the slower of the two. Personally, I'm probably not dumping 4 lbs of powder without trying it. I wouldn't use it for load development, but I'd load maybe 10 rounds, and compare the MV on those rounds to my previous known loads. I bet they won't be more than 5-10 fps off. If so, I use them for practice or varmit loads. If they are more than 10-15 fps, or any signs of pressure, then I dump it.
Ps, my bad, was the half full container 1 lb or 8 lbs? I assumed it was 8 lbs. If 1 lb, that makes if a bit different. I'd still test it and use it for practice, yotes, etc.