Weezing's SDef is pretty low, I would advise you to go totally Defensive. And Pain Split is better, in my experience. In addition, I would alter the moveset a bit.
Weezing (M) @ Black Sludge
Tarit: Levitate
EVs: 252 HP / 252 Def / 4 SAtk
Bold Nature (+Def, -Atk)
- Clear Smog
- Flamethrower
- Will-O-Wisp
- Pain Split
This is one of the most used sets. Weezing's 65 base HP allows it to easily abuse Pain Split with. RestTalk might help you with burns and HP, but its basically setup fodder for boosters sometimes. Now, I advise you use a Defensive spread, as that is what Weezing is meant to be. Clear Smog allows you to take care of boosters, and its STAB was well. Flamethrower is highly recommended over Fire Blast, as Weezing is a staller, after all. The extra PP from Flamethrower, the extra 16, will help you. Hopefully you know what Will-O-Wisp does. Pain Split is ultimately the better choice, as it does not force you to switch when something like a Kadabra enters the field. Any Pokemon with a super effective move can switch in and screw you over. That forces you to switch, which causes the Rest counter to reset.
Pain Split > RestTalk