A mate of mine reckoned that you can get a double sided diaphram with two nipples. One going to a source of venturi vacuum, and the other going to a supply of manifold boost. that way on boost (all the time with my set up) the timing is retarded to take the load off the pistons when the charge is really getting crammed in.
I think 1200RC has something like this, but I'm waiting for a reply to my PM.

It's like torture, not being able to screw my engine right out to the redline. (without hearing that blood curdling ratle) It's like being impotent at an orgy.(of supermodels)