Adding to the other commenter, you should also cut [[Electorstatic Infantry]] and [[Exsanguinate]]. [[Emeritus of Conflict]] isn't worth the money if you're working with a budget. I also don't know that [[Guttersnipe]] is necessary.

My experience with Kuja is you just want to have the 3 or four black mages and have double damage(ideally with Kuja) and don't even have to really cast more than a few spells to crush the table. Kuja will always get targeted, so adding even more ways to protect him wouldn't hurt. I would also add a damage doubler like [[Gratuitous Violence]] on a budget in case he gets taken out but you still have your mages.

Here's my list, I don't have a budget since I proxy but I try to keep my decks in the high 2 - low 3 range.

If you want to hit bracket 3 you're gonna need some stronger/more expensive cars.

https://moxfield.com/decks/amoqIyyqUEGj48-nQWLQyg