Yep--I added a third latch too---Gordon posted a masterpiece on the subject--I think it's in the Knowledge section.
The middle of my top bow never did seal as well as on the sides.
I found some great rubber seal, put in two strips--one on top of the other, added the center latch and it does not leak. (I am NOT making this up!)
What prompted me to add the center latch was the need to tighten my saggy top by pulling the top fabric out of the bow and re-installing it after pulling it tighter. It all worked like a charm and my top looks so much better now. I have confirmed what I read here on the site---after the fabric stretches once, it won't stretch again. I drove it 1200 miles to Tail Of The Dragon last fall at 70-75 with tyhe windows in which makes the top act like an aircraft wing---the Bernoulli effect if you will--the top pulls up from the wind going over it and that's what stretched mine---very saggy and droopy.
Mike---if you want an extra latch I have one, and will mail it to you for nothing if you will give me your address and promise to come to Carlisle this year---Jack