There was a good reddit thread on maneuvers a while back. Highlights of the options offered:
1. Just make it athletics, against the regular KAC+8. The DC is the hard DC for that creature. 20+CR*1.5. Upside is that it's tried more often by players since a skill check is usually higher than their attack bonus. Downside is that it doesn't really work with a lot of maneuver bonuses and makes some items/feats/etc not work or OP.
2. Drop the difficulty to Kac+4, BUT also halve all bonuses to maneuvers. So your maneuvers are easier to hit, and someone who specializes has a better shot. Upside is that it's very easy to explain the rule. Downside is that it requires trusting your players to remember the rule and manually override any online builder they're using.
3. Make it opposed. Potentially cool, imagining two combatants, locked in a grapple to see who comes out on top. Downside it's an extra roll and the GM has to prep their maneuver bonus even if the NPC doesn't really do them normally.
Im running Threefold Conspiracy using #2 right now, though I don't really have that many maneuvers being used so I can't tell you in aggregate it works out. Turns out that interrogations don't often involve bull rushing.
