nice questions. .

All the tunings I use onstage are E type tunings, so the basic scheme is: E B E G# B E

Normally I’d be keeping track of intervals rather than note names, so “E” winds up being any tuning analogous to E with the same 1 5 1 3 5 1 scheme.
Anyway, it doesn’t matter if the root is C# or F or D, I still think of any tuning with the root on top as some kind of E tuning and worry about the note names later.

I wrote, arranged, and generally pushed toward the flat keys whenever possible because I liked the way Marteen sounded and played better in keys more natural to the Tenor Saxophone.
No skin off my ass to use a capo or tune up or down a half step if I felt protective about my guitaristic open string stuff for a particular tune, so lots of F on the steel.
No coincidence that F was Dave Lindley’s primary onstage electric steel tuning in El Rayo-X, and he was my biggest influence at the time, but I still would have leaned to the flat side for the horn.

Here’s the list:
E B E G# B E

E B E A B E (DADGAD up a whole step)

B D E G# B E (occasional G# up to A, but rare)

The “E” and DADGAD type tunings show up as C, C#, D, Eb, F, and F# for root notes but it’s all the same 1 5 1 3 5 1 or 1 5 1 4 5 1 interval relationships.

I do teach and practice 1 5 1 2 5 1, and I do play quite a bit of bottleneck in standard E A D G B E, but with few exceptions the onstage stuff stays pretty close to the E tuning variations listed above.

I love Keith Richards playing regardless of tuning, with a nod to Ry Cooder of course without whom Keith would probably have not gotten to the 5-string G routine.

Regal with Debashish was probably E B E A B E.
I’ll confess to not paying the slightest bit of attention to myself in his presence.

I didn’t understand the Stella/A question. .