Redesign orifice disk

[Mousehouse1]

I am using a mercdog/MSD bench design I would like to redesign the orifice disk. I would like to make it where I use individual disks that I can change to change the flow ranges. How could this be done and seal properly? I know where I can have the disks made but I need to make sure it seals better then what I have currently or it isn't worth doing.

I have also thought about making one big disk with four or five holes that use plugs to choose which flow range you get. I just haven't figured out how to do it either. I think the superflow 1200 and a couple of their other benches are done this way.

I will have a deck plate in the front of the bench so changing the disks won't be a problem.

Ideas or suggestions anyone???????????