Playing hymn tunes for an hour or so daily has given me the opportunity to do a bit of fiddling about with making the difficult keys sound nice without too much slide shunting or note bending. And I'd be interested in hearing what ploys anyone else has found useful.
I'll kick things off with D major, which I used to find pretty horrid. If you've tuned your B to concert A, then none of the notes feel right.
Open G is a bit sharp, E nasty flat.
2nd valve F# and B (which you've just tuned to!) nasty sharp.
1st valve D is nasty flat
1st & 2nd A, C# and E are quite sharp
1st & 3rd D is nasty sharp
1/2/3 C# & F# are awful per normal
Actually, I've found quite a good setup for this one. Pull 2nd slide about 2 mm (about 15 cents) to sort out B & F#;
1st & 2nd should now be very close for A, C#, E (slight pull on 1st slide if not). Pull 3rd to tune all Gs and Ds to 1 & 3.
Except for the usual tromboning on low C#/F# this seems to solve everything for the Yamaha at least.