Megasquirt EFI Lean Cruise Reality Check

Excellent follow up and good news. Glad the rotor phasing helped. Question, why are you waiting one second to pull fuel? Narrow that down a bit and I bet your popping on decel gets even better. I’d say your doin well for only a year of tuning. Nice work.
Edited to add:
Try leaving the afr alone at cruise and just bring more timing in. Add a few degrees at a time in that area of the map and watch the rpm/mph trace. At constant throttle, when the rpm and/or mph drop off it’s all it wants. Then change fueling and do it again.