The IVC point will matter at different RPMs, what I mean by that is inertia supercharging will affect it more or less as the RPM changes.

The chart above is ok to give you just an idea but will be different with different engine combos with quench or without, port desighn, how cod the intake air is or is not, runner length, reverse flow or standard cooling... many other things but strictly temperature speaking gives you a rough idea how it will be effected just by coolant temp.

For the most part polys statement is true, especialy with ethanol as it seems people are running very high static and dynamic compression with it and I never heard anyone with detonation issues. I have heard of at least one guy running 16.5 on e85 but I imagine the %15 gas was not ordinary 85 octane like the e85 at the pump.