This is my 1964 Wright/Sierra D8 6 pedals.

What can I say its roughly the same weight as the RMS Queen Mary, but its my favorite guitar to date, it works for me.

The front neck is tuned to Bb 6th and has seven tuning changes.

The rear neck (or closest) is tuned F13th and has 3 tuning changes.

Hi to Lo

Front neck, F D Bb G F D Bb G

Rear neck, F D A G Eb C A F

The great Western Swing steel guitarist Billy Tonnesen once gave some very sage advice ” think of your tunings as one big tuning “.

That certainly made sense to me, I also think its always good to have tunings in similar registers ie A6 and E13 ( or E7/E9 ) hence the Bb and F key  choices