Like I said the exact OEM YJ blade is the Trico 12-2. That's what they came with from the factory. ANything else may work but isn't what came from the factory. The rear wiper for hardtops is the same 12-2 as well. Though you can fit larger blades on there since it's only one arm working the area.
The differences are usually the frame and how it mounts. The factory YJ's were plastic and look like this;
11" will more then likely look like this:
They work but are smaller then the OEM for the YJ. CJ's used 11" blades but had a different mount. You can try to use a 13" or maybe 14" but you run the risk of having the wiper hit the plastic retainer around the windshield which isn't good. TJ's on the other hand used 13" blades but I've hear people using 14's.