Hi
And thank you for the answers, and the layout diagrams.
Correct, I play of course a C/G ?
My position on A1 & A2 RHS ( C#/C# & C#/Eb) is probably not the "most correct" layout if you read the books, but I am quite sure that there are several Irish players, who use that "system". And it was the system Jose Claro, the maker, who lives in Tralee Co. Kerry, suggested, when I ordered my Concertina some years ago.
The reason for him to use that system is probably, that many players, wants several options for the C#, so they can keep up the speed (without changing the bellows direction, or have to change finger), in for example D Major tunes, which is a quite common Key for speedy, Irish reels for example.
If i read, and interpret the diagram right, it is a matter of which note you want to prioritize, and how many options you will give some notes. The Jeffries system priority, seems to be many options for C# (B on an Bb/F) in both direction, and the Wheatstone spread out a little more, and dont give the same options on the C# (B).
And that is of course a little problem, when you are use to have these options, and espescialy when the fingers are used to travel a special way.
I Play quite many tunes in D Major, and A-Major, and there are lots of D Minor tunes in Swedish trad, many with C# in it. One example is "Trollpolska", who have been a Tune of the Month here, is an example of a very common key in Sweden, especially if you play tunes from Dalarna. Trollpolska have several C# , even though it is a D minor Tune. And there are hundreds, like that tune.
So i am little concerned about the option to just have one option of B, when playing on a Bb/F.