OK , So I DID Start in Jazz , playing Clarinet and Sax , but playing in 'silly' keys is only a matter of practice ! Was chatting to a lass playing some lovely Soprano Sax at a session , she said she plays in D G and A so much , she has to really think about Bflat ! And because I do it at a session (Quietly , NOT plugged in ) I am quite happy in C# and F# on mandolin !
As Compton said , grab an earful of Brass Monkey - Horns and Melodeons and guitars !!