The material used for bonding the formers, and anything else for that matter, to honeycomb structure is NOT microbaloons with Epoxy, but a mixture that is epoxy and microfibers. These give a finished appearance to balloons but are many times stronger. They are essentially a product that is micro fibers of cellular cotton. when cured the strength is astounding. The ones I have used are marketed by WEST SYSTEMS. When producing a laminate of Carbon\Honeycomb it is essential to add a small quantity to the epoxy mix due to the small gluing area on the edge of the honeycomb, the mix then forms a small fillet to increase this glue area by forming a bond slightly down the vertical edge of the honeycomb. I can not comment on the other glues mentioned due to no experience with them in this sort of application but the above does work well and is far less prone to vibration problems than a mix with balloons as these are for filleting applications, not strength.
Cheers
Zotandy