I have never used an official bud box design, but I have used, and misused several tub set-ups. Twenty some years ago it seemed fashionable to see how many cattle would fit in the tub. Now it seems more effective to know how many quiet cattle at a time should be sent towards a nearly empty alleyway.
One permanent setup I have used a lot involved a long 16' alleyway that met the tub gate and a 12' gate into a pen that offset the tub gate by about 30 degrees. A six foot high solid gate closed at the proper spot so cattle "escaping" the crowd pen were diverted into the tub.
The tub led to a 30' curved alley with a self catch chute. Myself, one of the owners of the cattle and one other cowman disguised as day-help, ran around 180 head of replacements through this setup to pull CIDR'S, and give two shots in an hour and twenty minutes. We were in sneaky slow mode, which usually gets it done the fastest.
I'm sure that is not a record time, but it was part of a 68% catch to synchronization.
I have seen the exact same alley take three hours to give two shots to 120 mature cows. Same crew, plus one dog. I thought it went pretty smooth...
One common theme I have read in many forms is it's probably better to be short one good helper, than to have too much help, no matter what the working set-up.
One other thought I haven't heard addressed; I would pay attention to how sunlight/shadows will affect any corner or crowd point in any system. I have used several different setups that function a lot better or worse depending on the time of day or year.