I think I need to do some research before making a decision about switching from a Wheatstone to a Jeffries layout. I could get used to the different button configuration on the right side and the extra C#'s might come in handy. I play mostly with small groups consisting of mountain dulcimers, with a few guitars, flutes, a mandolin and an occasional fiddle. We play most tunes in the key of D, with some in G, A, and Em. I don't need a very loud instrument as I don't want to drown out the dulcimers.
I have seen some posts that mention that the reed pan is constructed differently on the Jeffries vs. the the Wheatstone and I am not sure how that would impact the tone or the durability of the instruments. Any advice or feedback from other concertina players would be appreciated.