In the interest of keeping this a bolt-on type mod, I'd like to stay clear of any patches or even tuning requirements. Fixed dwell probably won't help - the problem is the output being driven high when the PCM turns it on. If there are spare outputs that are high impedance when off and switch low when turned on (i.e. N-channel fets) that might be helpful. But I would only go that route as a last resort.

I think I have the cranking dwell issue figured out. Instead of creating a separate table I used a different dwell target for RPM < 400 and then added a bunch of columns in 25 RPM increments from 25 to 275 RPM. Going out in the garage to test shortly.