Current panels are rivetted in place and are approximately 1mm thick. 

I've not used the easy composites foam but I do use Gurit M80 a lot (closed cell foam also) and honestly cannot see the advantage of using honeycomb on a small area, especially when not using prepreg - it's a pain the proverbial having to multistage the process rather than one shot in the bag 

Honeycomb will collapse with repeated point loads (like standing on the thing). I'm replacing a floor panel at the moment on a boat that has had the core collapse, 1in honeycomb with 1/16 ali top and bottom