I put a velocity stack on a BSA 500 single back in the early 70s. When my throttle slide wouldn't return all of the way down because of the rock that had weaseled in past the screen, I rethought my choice of intake filtration. I was no longer one of the cool guys but I was able to learn how to deal with it. Suppress ones ego, Grasshopper. Kung Fu was big on tv at the time.Good one! I already have a Dremel though...maybe there's a special "round hole with flat" cutting tool I could convince my wife I need!
I've decided to make a small plate that will attach to the battery box bolts that held the original air cleaner back plate. The switch will be mounted to the left (as you sit on the bike) of the centerline of the batt box so it will be mounted 5-6" below the left carb velocity stack facing forward. The rear of the switch will intrude into the battery compartment but with the Shorai 18AH, there is no issue due to the batt's small size. Only issue with that placement is that it makes turning on the lights a bit of a reach, though workable. It does not require any wiring changes at all. Just need that special tool to cut the hole!
Hey, after a rather short period with the velocity stacks I may decide to just put the OEM air filter back in place/remove the stacks. We'll see...
Ironically, I would give anybody else the same advice - do NOT run without air filters! Heck, I don't even care for KN filters because they don't filter as well as pleated paper and here I am with brand new carbs and velocity stacks that are wide open - no screen or anything. EEK! 
swooshdave, do you mean in terms of weather protection or visibility to thieves? If it's the former, there a rubber cover available for the MkIII (part no. 60.4335) that fits the top of the switch and should help to protect the inner workings.
That looks very much like the bracket that my new oil pressure gauge has. I wonder if there's room on the plate to mount an ignition switch too!
