Found the thread. I imagine you could compensate for higher fuel pressure by advancing or retarding the IP timing as needed. Just be aware that once you go above 8 psi or so it starts changing the IP timing. So my saying 10 PSI is too high isn't exactly correct, just that things change once you hit that high of inlet pressure.
Official test results of fuel inlet presure/timing
There was some debate a while back about the effects of fuel inlet presure on timing. I had negative experiences with a gas EFI pump, and others were running pumps greater than 7 PSI, but less than the estimated 50 PSI that the gasser pump was pushing. Somewhere in between... I said, must be a...www.oilburners.net
So would only cause a loss of 1 to 2 degrees of timing curve at idle running 10psi, and in turn have idle slightly advanced. That is not much too worry about and the 6.9 ran fine without changing timing, and the pump keeps the pressure without a check valve on the return from the ip. So Im going to leave it how it is, since works and will not starve the ip of fuel.