I can bracket 6 notes if I use the "triplet" toggle, but they are labled as triplets. How can I change the number from 3 to 6 in the bracket?
Bigger problem... How do I control where the bracket goes on the staff? They are now much below or above the notes, making for a very large score.
Sadly you cannot change the number, presently NWC only supports triplets, but as you have found they can be applied to six notes as well as three - indeed to any group so long as it is a multiple of three. You might like to add you name to the wish list for support for ntuplets!
So far as I can see the number will always appear on the same side as the stem. You could add that into the wish list too.