Paul,
I mapped out a (rough) rotor face cycle, to get idea of the 270 degrees
that your using to calculate the injection timing and the only way I can
see it is from the closing of the exhaust port ( fully) to the opening
of the inlet port ( fully).

I have enclosed an attached diagram.
Please advise if this is an incorrect assumption on my part.
George ( down under)

I have not had a chance to study it as I am running out of time at the moment.
Robin's birthday bash is on Saturday and I leave for the east coast on Monday
and then on to OSH.

If anybody wants to come to the party let me know. If you fly in Oxnard
is closest and I can have you picked up at the airport. If Oxnard is down
due to weather SZP is not far and usually  weather free.