J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment Deck core

I'm going to replace the soft core in the dock of Sleighride, hull #55. What is the thickness of the balsa core on the cabin top? Is it the same on all of the deck? is there balsa or a different material under the winches, clutches, cleats etc on the cabin top? Has anyone used foam instead of balsa when replacing the core? Thanks!