propane and high compression

Hello everyone. I'm new to this site and would like to ask if anyone out there has experience converting from gasoline to propane. What compression ratio, do you think, would be the highest that will be compatible with propane? More specifically, for a Suzuki 660 cc 12-valve? This engine is very resistant to detonation even on low octane (92 octane) gasoline. It flat refuses to knock even if I lug it down at low rpm climbing up a hill! I don't know what the stock compression ratio is, but it can't be that high considering its low knock propensity. I know propane has an octane rating of anywhere from 105 to 110+ and would like to maximize the engine's thermal efficiency by increasing compression ratio to the max possible. With gasoline prices going through the roof nowadays I'd like to do my share in alleviating the situation. Thanks.