While I haven't tried Bullseye, I can say that my Uniflow doesn't care for Unique, another flake powder. I generally pour powder into the hopper until it's 1/2 to 3/4 full. I tap the side of the hopper to settle the powder, then start throwing and weighing charges until I get the screw adjusted. I get better results with the screw on the "front side" of the measure; i.e., the screw and handle alligned with each other and pointing down when at rest. This allows the powder to flow into the cylinder with the cylinder at rest and thereby eliminates the concern of, "Did I give the powder enough time to fill the cylinder?"
Uniflow will mostly throw +/- 0.15 grains with Unique for me; even better with a ball powder.
A lack of planning on your part does not necessarily constitute an emergency on my part.