Blast, this may be a little difficult with your stats. Your characters are pretty low to fighting him actually, and I'm amazed you've gone this far. Don't get me wrong, I'm not insulting you, just making a statement. Well, let's see...an effective way to take down Safer with your stats..hmm

-Distribute your two Enemy Skills equally among two characters. Preferably, your best Enemy Skill with the character that has the most HP, in your case, Cloud. The other Enemy Skill to Vincent as well.

-Stack Cloud with the HP Plus, Restore, Mega All, MP Plus and Revive Materias. Owing to he's the strongest you got, you'll have to make him the healer as he's the only one that seems to be able to survive longest. Alternate between healing, reviving, and casting Big Guard when necessary. How you're surviving Shadow Flare and Super Nova stumps me, as those attacks have always hit 5000+ on me. Must be because of your levels...

-Give Vincent the Counter Materia. It's been awhile, so I'm not sure whether Vincent can even counter, but if he can, he's the only one considering he uses long range attacks.

-Make Vincent your primary fighter along with Cid. Have Vincent uses his Enemy Skills and whatever other magic/skills you have but failed to mention. You said you had DB, which I presume is Debarrier. In this case, give this to Vincent BUT only use Debarrier on Safer. Casting Barrier and MBarrier is wasting turns, and casting Wall is too much MP. Leave Cloud to protecting everyone with Barriers, as he has Big Guard. Trust me, I fight him everytime with Big Guard, and don't even think of Wall.

-Give Cid the MP X3 and give him your summons. If Kjata and Neo are the only good ones you have, leave it at that, as Ifrit, Choco Mog, and summons like them are realatively ineffective against Safer. Just remember not to give Cid too much summons, as they are a big HP leach.

So basically, you'll have Cloud healing, reviving, and casting Big Guard when needed while Vincent pounds Safer with whatever magic and Enemy Skills he has. Cid will act as your summoner, by summoning Neo and Kjata that will hopefully contribute a good amount of damage. I am no personal fan of Kjata and never use him, but if that's the best you got besides Neo, go for it. Also, Safer does use Shadow Flare, so providing Cloud survives it, he will learn it immediately. You could use it on Safer, as it's a great attack, but be absolurely sure your characters are in goof shape. With such attacks as the Pale Horse, Super Nova, and Shadoe Flare though, I'll doubt you'll have much opportunities to do so.

Of course, remember to Debarrier Safer whenever he casts it and have Cloud recast Big Guard if he removes it from your guys. Use Limits efficently, but don't use Vincent's, as he will be of no use to uncontrollable. Also, don't immediately use them if you're in a bit of a situation, like put healing and reviving and other supportive actions before them as next turn you may regret it if Safer hits you good. Other than that, I have no other ideas and wish you luck with this and hope you beat the game.