I seem to be asking a lot of questions...
How do barker lever couplers work? Is it possible for barker lever couplers to drive keys AND not couple through (i.e. playing on I with II/I and III/II will play keys on II but not as III)? Is it possible for barker lever couplers to drive octaves and sub octaves on the same manual and not drive the octaves and sub octaves of the rest of the manuals (maybe by only driving the keys halfway?)
This is quite specific, but I am curious.