As others have posted, you can roughly just blend all these confused numbers RON, MON, AKI.
But the important consideration is:
what fuel rating do I need to keep the worst cylinder of my engine from detonating and damaging parts so badly that the engine must be rebuilt, or even replaced?
In the past, were there any groups who had an urgent, life or death, worry about what fuel rating to use?
Yes, the USA Army and Navy during the years when they were using gasoline like fuels.
They rejected RON and MON.
They researched the challenge and came up with the
Army/Navy Performance Number
commonly shortened to
AN-PN.
Gasoline powered aircraft fuel providers still give customers this number:
https://warteraviation.com/fuels/avgas115-145/AN-PN is far more scientific and should have been used instead of Antiknock Index on USA gasoline pumps.
AKI is one of the best examples of how bad decisions are made in Washington DC.