I am learning slide (slow a comin and not play-ready yet by a long shot!), albeit in standard tuning. But as I'm learning and experimenting with various techniques, I'm finding that it all really comes to personal taste. Glass sounds markedly different from brass, and brass from chrome. And even within the
same material, the weight, too, affects the timbre you get. It may sound like a cop out to say it, but truly, the right slide material is the one you like. Fwiw, I arrived at brass. Then the tough part: how the heck can I make this sound musical

Edward