TubeNet

Keep in mind you have the expertise AND tools/machinery to 'tweak' your tubas perfect. 99+% of tuba players don't have the expertise or 24/7 access to such tooling to do that with their tubas
That said, I'm not sure I want my top slides loose and trombone-like, where they can fall out if put on the bell. And I don't wanna mess with those stupid strings/laces on my top slides.
Thick oil or grease works for my slides

I wonder if lamp oil would be better than mineral oil when mixed with lanolin, or might it be too thin?

Nose grease is an outstanding lubricant for fly rod ferrules.

Dan Schultz wrote:Nose grease is an outstanding lubricant for fly rod ferrules

Perdonally, I prefer to smear it on my telescope lenses, and occasionally use it to remove excess head from my beer.