You may want to ask someone to craft a level 100~120 guitar so it can get loads of durability (you want a durability weapon crafter). Max durability is 250, I believe. Once you get a decent guitar, enchant it, THEN upgrade it. For some reason (like 90% of my BL) they like to waste ely/resources and upgrade first THEN enchant. Yeah. Okay.
ALSO! I can help you enchant if you need someone with a title (I got 99%-101% with an enchantment remedy or advanced enchantment remedy).
"He who fights and runs away, lives to fight another day!"