A few suggestions for your vary useful new panel, a "restart" from beginning button to quick reset back to the first keyset. Maybe this could replace the fast backward?
I see no reason why you need to fast backward?
"Restart", "Scan" and "Pause" would be more user friendly IMO. Scan being nicer than holding the fast forward button down.
Also "add current keyset to favourites" would be useful.
That makes six buttons so could be same as main screen layout?
Finally, do you realise that when using the fast forward then next keyset the application has to be restarted to run the fast forward again?