Any way you look at it, spark cuts, fuel cuts, and throttle cuts are all power cuts.
Better to keep the engine flat-out thru the shift without any cuts if you can. Even if you have to push the clutch pedal to initiate a full power gear change, the resulting rpm flare is evidence of energy being stored while power flow was interrupted. That stored energy then gets put to work as the engine gets pulled down after the shift is completed.
Grant
You are talking a millisecond of power interruption. No way is using the clutch a better solution.
Clutch operation offers more variation in ET - the interrupter never varies.
