how much compression for pump gas

FWIW,

I read an article where they did some testing on various octane boosters. Basically what they said was if you use the over the shelf bottled stuff you on raise the octane of the fuel a few tenths of one octane number. When you see adds about it raising octane by 4 or 5 points what they really mean is 0.4 or 0.5.

So, 93 octane with the prescribed amount of octane booster will be 93.4 or 93.5. The article also said that adding more than the prescribed amount provided diminishing results so quickly pass the price of race fuel.