I just tested a stupidly simple deck in the Trainer:
Mark of Life
8x Emerald Tower
6x Giant Frog
6x Elite Cockatrice
4x Lucifrase
4x Golden Dragon
2x Improved Miracle (Yeah, I actually took the time to farm 2 miracles on the trainer. I have no life.)
It farms Halfbloods about 66%, and it would easily jump up to 90% if I could add 2 Miracles and take out 2 Golden Dragons.
I also tried it with Epinephrine instead of Golden Dragons and Horned Toads instead of Giant Toads, and it worked just as well.