first I want you to understand that you have the older style latches that were changed right around 2014... some may tell you that you can adjust them, but that is only for post 2014 latch styles...
I have read that you can find and buy rubber seal by the foot and peel off the old and replace with new. Searching for the proper seal type to replace takes some web searching.
Some owners have added gutters above the top seal to eliminate the need to replace the seals.
One thread I found for you is here...
Over the years, but not necessarily recently that I recall, there have been threads discussing other types of self-installed gutters above the bed... you will have to use advanced search to find those threads. I would concentrate on pre-2015 posts.
Personally, I can find up to a measuring cup (usually less) of water in my front bunk at times. I don't worry about it since that water is always sitting on the VINYL (not canvas) tent top and does not migrate anywhere into the inside. It only happens on the front bunk and never the back or side bunk. My hybrid is normally under cover when not being used, but the front can get rained on... and possibly the water intruded when I was driving in the rain... hard to tell.
I do use a vinyl protectant product to keep my canvas in top shape.