Regarding the 6x6 sequential using mega, the injection and ignition side using timers works great, but you need to choose if you wan't to have igntion or injection sequential. I also have that mentioned software trickery to run ignition sequentially with 3 timers, but I have only got it working like 95%. Tried many things but still there is always some combination that causes wrong behavior. So I can't say it's finished. For now the 6-cyl sequential injection and Wasted COP mode has worked great in 6x6 board design.