Tested a LOT of different routes with different subposes and delay timing and interrupts etc, so don't be fooled by small low rerecord count. I was able to save more than 1 frame to get "similar" knife thrower in 2-2 last screen.
Saved 2 frames after jumping through guardian of ladder 2-1 with the earlier 1 frame improvement (3 frames saved).
Currently I get worse knife thrower at 2-2 last screen (slot5, knife slot 4), it looks easy to fix, however later input needs to be revised.