I have a bass that I don't want to get setup because it's real cheap. But when I tried some heavier guage strings on it and played for a while the plastic nut cracked and the neck got a bit bowed. I have loosened the strings. I would like to put a new nut on there, adjust the neck a bit, and then put some light guage strings on, Can I do this or should this be a job for a qualified tech? Thanks!