A better way to do this would be to close down all 4 of the air screws first, then start the bike. You'll need to use a throttle lock to get the bike to idle as you closed off all the bypass air. This means that only air going through the throttle plates will get to the engine. That way you can balance the plates (at idle) where the vacuum will be the most effected by small differences in the angle of the plates. No need to try to make the adjustment at 4k rpm, though you can easily check it if you want. If they are balanced at idle they should be balanced as the throttle opens. When you are happy with the plates open all 4 air screws an equal amount (~ 2 turns) and then re-balance them at idle as normal.
Fred,
Have you tried this? The logic, at least on the surface, sounds impeccable.
This is worth a thread all by itself, if you ask me, since it makes more sense than the Unauthorized version at 4K, or the modified Unauthorized version, from Jestall IIRC, simulating a load by killing a cylinder by unplugging an injector. Or was it Radman? Too lazy to search.
Did this idea recently come to you, or have you been saving it to give it to the forum as a Christmas gift?