For starters, I'm not sure why everyone is getting hung up on an MCBR. None of the Intamin Hypers use them, and Millennium Force is the only one that runs three due to having a separate unload.
Secondly, if the ride time is 3 mins, then the dispatch interval cannot be 3 mins because you'd end up with a situation where every 2nd train would be stacking behind the one in the station (In other words no point running a 2nd train)
The correct maths is to acertain the loading time, add that to the cycle time, and then that is the number of laps each train can do in an hour.
Then double that because you have two trains running, and one train can be let off the lift as soon as the other has cleared the first brake run.
So say they could check a train in one minute, that means a cycle time closer to 4 mins = 15 cycles per train.
So 30 trains per hour = 660.
But then again, that 3 min figure could be inclusive of the load/unload time.
Flash is 2 mins from station to brakes (Video was taken in testing with a slow lift) but the Alvey POV seems to show the lift going faster but unfortunatley cuts most of the lift out.
so 3 mins total cycle including loading could be a realistic upper limit?
In which case 40 trains per hour can be sent, which is 880 per hour.