No you don't let off on the throttle when you shift.
The computer handles the throttle during the shifting sequence. Let it do it's thing: you only need to hang on! :2thumbs:
As I understand these semi auto paddle shift setups, not only in Spyders but other vehicles too, the throttle is not altered by the computer, but rather to get the instant shift, the ignition is cut for an instant to unload the drivetrain allowing a quick shift. Moving throttle that quickly would take longer. Also, ridden with heart, you get that upshift bang, typical of an ignition cut and refire. One of the coolest things about the Spyder. WWAAAHHHHHH, Bang!, WAAAAAAHHHHHH, Bang!
I have found to shift when it is just running even speed.