Gitane 255 problems

Sonofmickel

I recently acquired a Gitane 255. It is not without its problems. I have shimmed the bridge with three picks per side, high E received a purple, yellow and blue Dunlop Tortex, low E received a purple, blue and red Dunlop Tortex. IT STILL HAS BUZZ!!! I do have relief in the neck. It appears that the fretboard that lays on top of the body has a hump in the 13-17 fret area. Should I get the fretboard ground and refretted?
Another thing- the zero fret has already started to get string pits in it. When I bend strings aggressively near the nut possition the strings "pop" in and out of the grooves in the zero fret. Is this normal, or do I need better frets(ie..harder, better nickel)?
Also-----the B string seems to be of lower tension than all other strings and it has buzz pretty much down the entire neck. I am using Del Arte' lights.
I realize that these are cheap guitars, would I be better off getting the DG300 or just bite the bullet and get a handbuilt?
I have been playing for 16 years so this is not just a hobby, it is an expensive hobby!