How much aux brake effect should I be sensing?

I should have added more detail around "everything appears to be working". When the toad brakes are activated from the MH, the vacuum pump in the toad kicks on and there is movement in the brake pedal. If I really stab the MH brake, the toad brake pedal is moved more. So I believe the system is performing at some level.

I wonder if it is possible that the toad brakes are so small that they have no effect on the MH...