I just used wood glue for all my r13. It all had that paper backing on it so I just squiggled some darting lines across it and placed it on the wood. I held it in place for maybe 10 seconds and let go. None of it ever fell off or anything. Worked pretty well for me. I had thought of using spray adhesive too but this worked like a charm.
For the most part, it sounds like you're getting a really nice and extended response and that's great! All the other problems you're having are directly related to all the EQ stuff you're doing. A boost will DEFINITELY get your amp clipping. You're robbing yourself of a lot of power boosting one spot. Also, Dynamic EQ (if you are indeed using it) is making things worse. Turn it off. All it does is give you a hundred different frequency responses. Lol. Start from zero and then work you're way up. I'd try no EQ of any kind, listen to some stuff and then go from there.