How do you notate one quaver out of a quaver triplet in a bar of 1/12? Do I need to put a half bracket with a 3 below it, or leave it as a quaver since its base value is already a quaver triplet?
If you put a bracket on it, it would make it a triplet within a triplet, which if I understand correctly, is not what you want. In any case, that's not possible in a 1/12 bar anyway, the bar would need to be at least the length of a triplet crotchet to accommodate that. The time signature change is enough.