I know of another guy in SO CA that worked in a knock lab also, he lead me to use the projected tip spark plugs in iron headed B and RB motors as well as all of the Mopar hemi motors for drag racing and street use
Same information, different conclusions
I had low compression(true 8.5 to 1) pump gas 350 Chevy boat motor that pinged, knocked, on regular pump gas with a Champion J12Y and quit knocking with a Champion J11Y
I worked in service stations a long time ago before they became gas stations only and I have seen many stock motors that needed the spark plugs heat range changed for the driver
Around town only grandma drive differently than there hot rodder grand kids did
Colder is always safer than a tiny bit to hot when it comes to gasoline and different driving conditions and fuel used