I've done aerocap before with feet on a step placed behind a door-frame mounted finger board. Had a BM2000 with a medium campus rung below it and made hand movements between the campus rung, deep slots and 20 degree sloper. Modify difficulty by moving the step forward/back and having either both feet or swapping between feet on the step. Have a podcast or playlist ready to stave off tedium. Think I'll be doing this again now!