Ill have to give one of my VFDs a try and see what happens.
The cable length should not matter. They make the cables that way so they can sell you a real expensive cable every time. These things dont run at a high enough frequency to worry about the effects of cable length.
Look in the manual and see if it specs anything about the cables or if it list the connector part numbers. Or just give varian tech service a call. I am sure they will tell you what you want to know. But watch out putting the control on different turbos. Who knows, they may be designed for the parameters of motors specific to one model of pump.