Wheel hop in REVERSE?

If your pedal is using up all the travel just to achieve departure, then it becomes very difficult to modulate the pressure. Ima thinking you have the wrong pedal ratio.
Adequate departure should occur, I'm guessing, at less than 60% of pedal travel.
Also; If you have a diaphragm clutch, then it has flyweights on the fingers which slide up and down the fingers to change the clamp-load with rpm. If they stick on, then you get clutch-chatter on engagement, and vibration until all the other weights come up to the same position. They are all connected together with a big ring-spring, which is supposed to synchronize them....... but it sometimes forgets what it was designed to do.
In any case,most of the time, you need to modulate your engagement with a low-enough rpm that the flyweights are all still on the bottom. If you have hiway type gears, low compression, and a big cam; then often the engine doesn't have enough power at said low rpm to take off briskly. The reverse gear in the A833 is exceptionally low in number offering very little torque-multiplication, and so requiring a bit of rpm to get the car to move. If this rpm gets the flyweights moving, and some of them are not moving smoothly. then chatter would be the result. And the chatter at the clutch, combined with weak leaf springs in the back, could I suppose turn into wheel-hop. The wheel-hop gets into the chassis, and then into your foot because it is resting heel-on-the-floor and that just aggravates the departure and round and round it goes until you floor the clutch. A lumpy cam just makes it worse.
So while the washers have given you relief, IMO temporarily, I think your pedal ratio may be wrong; slanty pedals are different from V8 pedals. Some guys have re-engineered their slanty pedals to work with V8s, and there are a few threads on FABO to show you how this is done.
Again, with the freeplay set to about 1", the trans in gear,engine idling, and letting out the clutch, you should have about 1.5 inches or so under the pedal, to the floor, when the clutch begins to affect the engine. If you don't, it will be hard to modulate the engagement. And any vibration in the floor, if your heel is on it, can/will be transmitted to the clutch out the driveshaft, and back into the rear springs.