I just got my buffer up and running and so far it sounds great

I am going to get a 6h30pi to try next.
I have read the these tubes run quite warm and was wondering if anyone has tried a "tube ring"
like Herbie's or the like.I haven't seen any photos that have tubes with rings...
With how the tube is mounted I'm not sure if they would fit...

Also in general do these things make a difference in sound quality??