Kind of a bummer to have spent hundreds of dollars on equipment at Jake's urging only to find that it's now unnecessary and obsolete, but he's experimenting and learning as he goes, just as we all are.
I've screened powder in the past with decent results, though I had to double my powder charges to achieve comparable velocities as commercial powder. Like I was explaining to Kevin... who really cares if it requires extra powder, though, when you can make the stuff at such a very small fraction of what you'd pay for the commercial equivalent. It's inconsequential, if you ask me. This is how it was done up until the late 1700's, so it ought to be good enough for you and I, right?
I've got quite a bit of Pyrodex from when I was first introduced to muzzleloading. I'm seriously considering using the stuff in my fowler cartridges, with a 10/15 grain "booster" charge of holy black sitting on top of the cartridge, and priming the pan with my priming horn. Thought perhaps I might be able to make my existing black powder go farther this way, although I'm fully aware of the drawbacks.