OK good news on slot 1. I’ll check out slot 3 version anyway despite my previosu post on a possible different approach to compatibility.
Just re-reading your mail. You said you have pawn in slot 4. That isn’t going to work as the main scope Apps like stock, community and Wildcat take up 2 slots. So if you put Pawn on after Wildcat then it would have wiped out half of Wildcat.
This is what is interesting about the Fourpack approach it splits up larger apps so they only use up 1 start up slot and put the rest of the code in spare ROM capacity in the background.