You may have already figured this out, I'm mentioning it because you haven't mentioned it, just in case. Hope it helps.

Enchantments get more expensive to put on the more you already have piled onto an object. Before starting it's usually good to compare the cost of each enchant applied and then put them on in order of most to least expensive. That way the least expensive will be expensive by the time you get to them but hopefully won't have gone over the limit of how many levels you can use to apply it.

This. I have never even owned a suit of complete full on god gear before Blackfish came along. So now I just enchant pieces of armor at lvl 26-30 anf then buy the books from Blackfish to fill in the gaps.

Also the adjustable enchanting table is not just a toy. Mine are fully adjustable but if you can get just a few bookcases on sticky pistons then you can easily look for enchantments on the lower lvls. For example a firepro4 chest @lvl30 may be a ub3 at lvl 26 which is much better for you. It is especially helpful when looking to create rare books.

Another thing I do Is each time I enchant I have all the gear ready. Hat, Chest, Leg, Boot, Sword, Bow, Book, Pick, and maybe axe and spade too.

I should be able to find something good if I check all of those on every level. I hate wasting a shot so I rarely enchant a waste item.