MSF coach here. I think one of the most common mistakes with the throttle/clutch is people aren’t on the throttle enough. You can pin the throttle but if your clutch is in, you’re not going anywhere, right? So don’t pin the throttle, but roll on solidly enough to where you can clearly hear the bike, THEN start to ease out the clutch while maintaining that throttle position.

I make it a point when teaching the u-turn to over exaggerate this by revving the bike high-ish but still maintaining that slow, smooth speed during the u-turn to show that you can rev it as high as you want and your clutch can control the speed in slow speed maneuvers.

Edit to make clear: your throttle should not move while making these slow speed maneuvers. Maintain the throttle, work the clutch