Sounds sweet
Remember that once you toggle into keyboard mode, you have top use the normal keyboard-mode controls to get back out. It is unfortunate, but makes sense.. otherwise, think, if you rebound "B" to do something, then when you went to keyboard mode, "B" wouldn't work anymore, right, to push keys? So only Custom mode honours your bindings..
So it is best to bind left shoudler to keyboard, since then you can push left-shoulder again to get back to Custom. (Keyboard Mode knows how to use left shoudler to go back to previous mode, as it always did)
As to auto going to Custom mode..
How about I add a command "modechange" and value "custom" to make it go to custom.
That way you coudl have a defaults.cnf that can go to Custom imf it wants.
(You might have a defaults.cnf that just sets repeat rates, but not controls, so you do not want it to go to Custom by default)
I can make 11.4 to do that tonight or tomorrow morning no problem
(adding simple command/value handlers takes 30 seconds
jeff