I was rereading the EL arc, and I started to wonder about this. So, Jyabura and Kaku were only 20 douriki apart. Now, when Sanji beat Jyabura, he was messed up but OK. When Zoro beat Kaku, I would say that Zoro was more seriously injured than Sanji was.
Does this mean that Zoro and Sanji are equally strong now (or at least close enough that they will be equal in the near future)?
There is the problem that Zoro's bounty is much higher than Sanji's (120 million vs. 77 million), although this can probably be attributed to the fact that Zoro beat a well-known assassin in Alabasta and Sanji didn't, thus giving him the advantage of having a bounty first (it could only go up if they accomplished anything, whereas Sanji would have to get a bounty first).
Have a good Labor Day!