Ran 100 octane for the first time. Wow

The only paraffin fuel I'm familiar with is nitromethane. I've never messed with Avgas, but I would not be surprised if it didn't somehow carry an extra oxygen molecule somewhere in the mix to help with high altitude combustion.
If your engine is on the absolute verge of detonation..which is generally inaudible, then I could see where a higher octane fuel would calm things in the combustion chamber and therefore give a noticeable seat-of-the-pants difference...but that's just a matter of putting a band aid over a poor tune.
As for the difference when towing...that's pretty much WHY different grades of gas are available. Anytime you load the drivetrain, you're adding resistance to the reciprocating assembly. That equals heat and heat leads to detonation.
One of the problems with the way we visualize things as they apply to our cars is that we divorce all of the individual systems from eachother to better visualize the various processes all going on at the same time. The truth is that the head of the piston is directly mechanically connected to the contact patch of asphalt under the driving wheels. BTW, that is the essence of the black science of Nitro tuning.