Core Replacement Front Cabin Top

[Stef]

I had water intrusion by the front block attached to the deck for the spinnaker down haul. Pulled liner down in the area and cut from inside. Total area of about 1 ft square removed. Mast step is OK. Removed all wet/damp balsa and left it open for a few weeks to dry out, all seems good now. I can get end cut balsa 1/2" thick (which is what came out) to replace core, or is there a better preferred material?