Static compression has very little to do with what octane fuel your engine needs, it is dynamic compression or cylinder pressure that determines much more the octane needs of an engine. Performance trends engine program will make a prediction on spark knock and will generate a spark curve to use if knock is predicted, very cheap insurance when designing an engine build. I have built pulling truck engines that had to run on pump gas with 13 to 1 static compression, and it did not detonate.