The overtone tuning is the
1-1'-5'-1''-3''-5'' 8-5-4-3M-3m
C2-C3-G3-C4-E3-G4
The two modifications are
1'-5'-1''-3''-5''-7'' 5-4-3M-3m-3M
e.g. C2-G2-C3-E3-G3-B3
AND
in order to have also more 5ths, we permute the last 4 strings as in the tuning of the post 194
3'-5'-1''-5''-3''-7'' 3M-4-5-6m-5
e.g. C2-E2-A2-E3-C4-G4 which is an open Am7 tuning
Still more variations are the
8-5-4-3M-4 or 1-1'-5'-1''-3''-6'' OR C2-C3-G3-C4-E3-A4 which is also open C6 chord tuning
OR G1-G2-D3-G3-B3-E4 As this is not very practical with the type of strings that exist the next modification is more practical
and 5-5-4-3M-4 as in post 219 C2-G2-D3-G3-B3-E4. The later may not be open tuning but
it has advantages of chord-triads in the lower 3 strings
ALSO
C2-G2-C3-G3-C4-E4 5-4-5-4-3M
We may compare the above variations of the overtone open tuning with the next 3rd variation of the overtone open tuning
C2-G2-C3-G3-C4-E4 (5-4-5-4-3M)
https://www.youtube.com/watch?v=pf9-_hHFo1A
