I'm planning to build some fiberglass hatch recesses similar to the ones built at http://clearstreamwood.com/WordPress/store/cf_hatch_recess (I have the molds made and ready, they will be used to hold a round and an oval VCP hatch).

Being that this is the first time I'm going to build something purely with fiberglass (no wood core), how many layers of fiberglass would you estimate I'll need to put to to make it strong enough (2, 3, 4?). If I put a CF layer first (like Dan did), will that count as one or 2 fiberglass layers?

Yep, I could mail Dan directly and ask him (he has been very graciously answering my previous e-mails very fast, thanks Dan!) but I thought of posting the question to gather ideas from the global expertise/knowledge (I find that everybody has different ideas and methods)

Thanks in advance!

Hugo