I just got in from working Cohort, and am pleased to report it went well. He was much more cooperative under saddle, not quitting once on me. I lunged him first, then used all the same verbal cues while riding. Kept it short and sweet, and he seemed pleasantly surprised.
Before riding I trimmed his bridle path with the clippers and sprayed him down with fly spray without reaction. The boy still has straight "A"s on his ground manners report card!