mode 7 background

also i have a hex editor, but which one do you recommend for ff6? what i mean is that is there a specific hex editor to change the bottom half of the mode 7 background?

No. Every Hex editor can either change everything you want or nothing. It's like asking which pen is the best to write an essay or which pen is made to write an essay.

As for Hex editor, I would recommand HxD or IVI32. They have their own special features. Most people like WindHex and if it would not support tables, it would find the way to my recycle bin very fast. Sadly, none of the three has a special feature made for FF3us exclusively that change the bottom half of the mode 7 background. We live in a sad world.