Overdue update, car is still misfiring on the K6 ECU. I sent it over to Emerald in April for them to review. Still waiting on a verdict.
In the meantime, I snagged a used emerald K3. Ported over my map.
Just got done confirming timing. I was able to get the car running, idle it is dead solid at a 12 degree advance (locked). When unlocked, and given gas, the timing mark moved to the right, it didn't jump.
I'm hoping this ECU is the culprit, and will go test it this weekend.
QED lightweight 1.4/1.6 Rover K series Emerald flywheel settings (in case anyone needs them):
36/4 EU2 Rover Flywheel drop down
Reference: 125 degrees (124 or 126 had a slightly worse idle). This is based off the idle stop screw being set to a good idle on the previous K6 ECU.
Will update later.