I recored my bulkheads a few years ago. The core was the consistency of oatmeal in some areas...not good. I did all the work from the head and closet side, leaving the veneer in the main cabin alone. The fiberglass on both sides is 1/8" to 1/4" (sorry I can't recall the exact size). I believe the core is 3/4". There is about a 2 sq ft area that the chain plates bolt through that is marine grade plywood, the rest is the usual balsa core. It took quite a bit of work to remove the closet and head cabinets, but then you have a nice big area to work with.

I also redid the backing plate with 1/4" aluminum. It was just plastic like what was used under the stantions.

Hope this helps,

Scott