I catch a lot of my badgers in traditional predator sets, like dirtholes and flat sets. I've noticed from my notes that bait sets seem to draw more than post sets, but both have connected well for me. Location seems to be key. Farther away from the normal travel lanes I make sets, the fewer badgers I caught. I started making canine sets at least 20 to 30 paces away from fencerows, weedy draws, etc. Maybe badgers hug the "edges" more than canines do, I'm not sure and my results are certainly not scientific by any means. I started doing it to reduce my possum and skunk catches, and I've noticed a definite decline in the non-targets by getting a little farther off the good travel lines like fencerows, draws, edges of fields, mowed lanes, etc.
I never had good luck finding active dens or setting on diggings. I believe a hole dug by a badger is more or less evidence of a mouse or other varmint that the badger has already excavated and moved on. But, that's my experience though and maybe others are more successful at these setups.
Jim-NE