I personally don't like sleeves, sloppy and noisy (I fish so noise matters). Wrapping is super easy. You'll need 75-100 feet of rope per oar. I like to use a little carpet glue under the rope because I think it makes the rope stay tight a little better than without but this is not science, just my opinion.
Here's a quick tutorial (not bad). Hope noone minds the link
Or you could buy a new pair of oarlocks and go without rope or sleeves. The sleeve is built into the lock. The oarlocks are made out of stainless in Idaho Falls by a machinist. They're not cheap (150 a set) but I liked them so much I now have them on all of my boats. I'll forward the number if you're interested.