There is currently no other way to add to a custom list, other than the menu...I will be adding some kind of shortcut once I decide on the best way to go.
The main list cannot be filtered & this won't change. BUT I am going to add an option or something to allow the main list to be skipped when hitting the list-change key. So effectively you won't even know the main list is there (for you, the 'main' list will now be say custom list 1).
Actually, you will be able to pick exactly which lists you want to 'cycle' with this key - so eg you could have a *mature* list which cannot be cycled to (in case of kids), but then you can unlock and select the list when the lads come round

Fortunately, I have no kids so this is not a problem for me, lol!