Pluses and minuses for the different fifth size

 Here I will shortly tell the advantages and disadvantages of three different sort of fifth quality.
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a) Pure fifths: This is the choice for the introduction above.

+ : Completely pure chords !!

- : But within a setup like C 0 with two D`s, you can`t switch between them
(Bbmaj/Dminor  and Gmaj). 
And with the shift halved which is the idea of this tuning, the shift can still be to big for some of you. 
The logic of the melody is not so good here.

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b) The fifth is narrowed with 2 cent, which is the same as in Equal temperament.

+ : With a halved comma shift, this will be only 6,8 cent. 
The ideal Vicentino`s second tuning has 5,4 cent, so it is close to this regarding shifts. 
The gap between the D 0 and D -2 in C 0 will be 13,7 cent , and that is small enough to use in many cases. Then you can avoid to jump between manuals so many times.
Regarding logic of the melody it will be better when the fifth is more tempered.

- : The fifth is now not better than equal temperament. (12-ET), still good, but the fifths in 1/4 comma meantone is just 2,75 x more narrowed, and playing with sounds with not so much treble the difference between them will be smaller and the efforts playing this tuning is maybe not worth it.

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c)   And so, in the middle is my favorite , 
        the fifth narrowed by 1 cent.

+     Pure major thirds, the fifth is nearly pure. When the fifth is narrowed by 1 cent, the comma shift is diminish by 2 cent to only 8,8 cent, which is acceptable in my ears.
It is also forgivable to have a comma shift of two units, occasionally.

- : You lose the totally pure chords, and you maybe lose the possibility to do a OK comma shifts internally on one  manual(eg between D 0 and D -2)  . But this is a matter of taste, of course you can do it. It also depends how close in time a note with two pitches appears.

How to get all the cent values from these alternatives will be explained further down in the introduction.(the spreadsheets)