I used an overhead crane on each end of the top to replace the front seal. That made it pretty easy to control the top. The dang thing still leaked when I towed in the rain.

Then, I opened it up and used a closed cell foam weather strip with an adhesive backing on it. I put the adhesive against the top channel after DE-greasing with a solvent, and using a little sandpaper on it. I may have loosened the hinge bolts to do this, but I didn't go back to the overhead cranes. Have an assistant shut you in the trailer, and then shine a flashlight into the gap. You can usually see where the problem is. Based on my results you may want to try this first.

Get the glider parts out of the trailer first,and be very careful to not let the top get away from you.