Is there a 10 string tuning equivalent to the alto tuning?
Keeping the same relationship between both sides of the board strings.

ie 7th fret 6th string= g2 8th fret 5th string =g3.

Deep baritone Melody almost has the same relationship, but the octaves are wrong.
Hmmmm.

Very interesting. I was taking a similar way, starting from Bob's Expanded Alto (matched reciprocal!), where the bass side is deeper, the melody side is higher than the Alto Tuning.

Current state: the bass side a whole tone lower, the melody side down a 4th. This is like the SG12 matched reciprocal tuning without 1st and 12th string.

And I discovered that this is the 10-string Full Baritone Tuning on the 5th fret:

Melody
1 D
2 A down a 4th
3 E down a 4th
4 B down a 4th
5 F# down a 4th


Bass
6 G
7 D up a 5th
8 A up a 5th
9 E up a 5th
10 B up a 5th

On the Alto this is working fine, similar to a baritone guitar or Fender VI range, but on the 10-string I still use the Matched Reciprocal Tuning, but I will give a try to the Full Baritone Tuning ...

Basically extending the alto tuning to the lower register. G in 6th string 7thfret may have to move to 6th string 12th fret. Then d2 would be 7th fret 6th string d3 8th fret 5th string.

shout out to Greg Howard!

He knows his Stick!

Tuned me up.
Thank you Sir!
Rock and Roll!....

Cheers, Rey!