Technical Question

OK, yesterday I bought 4 empty mantle clocks (and a violin case!) at a local antiques shop. Perfect for little theatres I thought... Here is my question. As you can see, I jumped right in and papered this one with music. First I gesso'd it, not sure why, just did. Then I glued on the paper. Well, the edges are not adhering as well as I would like them to. The paper is ancient, and wants to crack... Do I paint varnish over it? or something like 'modge-podge'? I also am thinking perhaps I need to add some kind of trim (ribbon?) to the edges. I am stuck. Figured someone out there may have a solution or idea to pass on. Thank you for your help in advance!!!