Spikes versus Rubber on wood floor?

Not that this helps but congrats on your new speaker, it should be a nice jump from your Polks!

I used rubber under my home theatre speakers (Athena s3/p3) and the sound was awful, affecting the bass the most.(bloaty, slow, and absolutely no punch, kinda like: bbllaaahhhhh) I used big heavy cones, and the improvement was immediate. Sorry, I do not recall the brand.

Speakers to perform their best MUST NOT MOVE AT ALL (meaning the tops should not wave around, even a silly millimeter!). So rubber is OUT! Spikes are best, but if you are on a wood floor, you have to be cunning about where you place the speakers relative to the supporting structure, in order to minimize the rocking motion that can result from the floor flexing (spikes won't help with that problem.)

So, how far apart are the trusses?

I highly recommend Herbie's Audio Lab Big Fat Black Dots. These were an improvement over the Audio Points brass cones previously used in my system. I have a fairly rigid engineered truss floor covered with plywood and oak flooring.

Herbie's Audio Lab