That's fascinating, thanks for the account.

I've found that any restriction on the ability to move your head can add significantly to the feeling of helplessness when in heavy bondage.

I've read a couple of reviews of the Scott gag being used where the attachment point on the wall was positioned so it was too high to allow kneeling but too low for the sub to be able to stand fully upright. This forced the sub to bend at the waist or adopt an awkward crouching/partially squatting position either of which rapidly became uncomfortable. Was this your experience?

In one account the sub had his hands cuffed behind him and pulled up with a strap running to his collar. He was then caned with the only thing holding him in position being the gag locked to the wall.

I would think having a receiver mounted on the floor would also be very effective. I've been forced to kneel with my nose pressed against a red dot on the floor and not move but I would think literally having your head locked in that position would add tremendously to the experience. I always prefer being in bondage vs being ordered to hold a position while unrestrained.

I love bondage gear that is wickedly inventive and I think this qualifies.