100LL avgas is rated any the lean/rich scale that's aviation specific although it roughly corresponds with 100 octane R+M/2 that's used to rate pump fuel. One problem with blending premium with race gas or av gas is its not a mathematical scale that determines your end octane rating. In most cases this doesn't matter, but in some applications it does. If your motor requires it run straight race gas. It's a fools errand to guess with an expensive race motor.
Octane boosters like Klotz raise your octane less then 1 number. Unless the treat rates get ridiculous, which introduces all sorts of problems. Most boosters use aromatics like toluene and some use MMT. MMT has a ceiling where by its ineffective and it produces lots of rusty color deposits which can cause pre ignition. The aromatic based boosters cause throttle response issues and are very hard on rubber and plastic, plus they are nasty to inhale, which is why they were phased out from use in pump gas.