In terms of twin carburetors, it would sound as if one cable was tight -this being on the cylinder that wants to "take-off" at initial slight acceleration. This would cause the uneven idle. Are you sure your throttle free play at the grip is adjusted correctly, via TuneEcu? With a 990 one cylinder providing all the power down low (the needle swing) is all down to the linkage adjustment, assuming your fuel and ignition maps are more or less identical in this area. You can check the butterflies move in sync visually or by feel (maybe a third hand needed). Any slight differences here will make a big difference near idle but will virtually disappear once the throttles are opened to a midrange and above. That's simple math. That being said, doesn't really explain your vibes all the way to redline. That sounds more mechanical in origin to me. I have recently found my pressure plate is all over the place at idle (clear clutch cover). My Rekluse is grabbing at idle too, so I am hoping a clutch rebuild will get rid of my vibration problems.