a 3 row box in GDA as yu suggest should not be a problem to special order or the alterations could be done by any competant repairer/tuner. however GD&A (with the lift you want) or not difficult on a BCC# plus you get lots of other keys for free! Also the bcc# is not as 'clumsy'to handle as a similer size adg as there is less need for bellows reversals and even a choice between the smooth route and the jerky route to some extent

the original argument I put forward was that the bcc# is a better bet for those happy with a 3 row box than other combinations of diatonic keys plus accidentals

more views welcome!

bb