Fleece to Fiberglass + Pics

Hello.  I've done a search, but didn't find too much on the issue.  I have a 10w7 that I am making an enclosure for.  I currently have the mold done and it is 1/4-3/8" thick and does not flex with the thumb test (I would feel comfortable standing on it).  I keep reading how important it is to make sure the box doesn't flex, but my question is this:  When I stretch the Fleece over the MDF ring and glue it onto the back of the mold, and then resin it, what should I do about the seams?  I feel like they are going to be the weakest part of the enclosure, and if I try to lay down too much glass at the seam (between the fleece and the mold), it will get too thick and not fit in the trunk.  What should I do to make sure my sub doesn't blow the box at the seam?  I don't think I will be able to access the edges from inside the box either because of the construction.   Here is a pic of what I already have done (before the 8 layers of glass).  I also included one of my amp rack without the false floor on it.  BTW-this is my first time at this.

Here's another one of the amp fans I installed--not really related to the post, but opinions/comments are welcomed.  Thanks in advance!

If you cant get inside the box to paint resin on all the seams mabye you could mix some resin with body filler

and make it just thick enough so you can roll it around inside the box on the seams... just an idea