The timeline panel is definitely the key for tween adjustments. You can select a keyframe and drag it left or right to shorten or lengthen the tween duration. For finer control, the keyframe properties panel lets you set exact frame counts numerically.
Thanks for raising this — tween length adjustment trips up a lot of newcomers. In my experience, the easiest approach is to select both keyframes and use the frame-count field at the bottom of the timeline panel. Dragging works too once you get the hang of it.
Thanks for raising this — tween length adjustment trips up a lot of newcomers. In my experience, the easiest approach is to select both keyframes and use the frame-count field at the bottom of the timeline panel. Dragging works too once you get the hang of it.

