Updates: I have found an issue : oneshotlayer (OSL) breaks when you map both function keys in the 2nd layer to a 3rd. Neither function will act as a one shot layer anymore when you do this. Not sure whether to create a bug report or feature request for OneShot?
My request would be the following:
If either fn is in OSL lock mode to layer 2, locking the other side fn would lock to layer3.
If either fn is in OSL lock mode to layer2, taping the other fn would give you a oneshot in layer 3 and then drop you back to lock in layer2.
If you one shot both functions one after another you get a one shot action in layer 3, and then you drop back to layer 1.
I think that is all the situations apart from the standard behaviours for OneShot.
For now I am rething my double function layer entirely, I may try a leader instead or perhaps I will use the butterfly for the layer instead of doublefunk!
@rumpel if you really do have a MC that does something better please reply and let me know what you did.
@algernon thanks for the reply. I implemented the layer design as you first mentioned and it functions as expected. I found that I can release one of the function keys and I will drop back to the 2nd layer, but it is dependent on what side fn key was pushed first.
I am still interested to see what @rumpel managed to do with his MC, but for now I have a solution which works well enough.