New Cuddy on small fishing boat

[Danshane]

Hi All,
I am just starting building a replacement cuddy for my small fishing boat.
It will bolt on to the hull just like the old one did. There are some pics on photobucket http://s694.photobucket.com/albums/v...y%20Extension/

The new cuddy will be higher and come further back than the old one does.

I have removed the old one, and my plan is to build a mould plug around this (without destroying it as I may need to use it again if my new one is a disaster )

I am just starting to build the plug frame.
Any advice would be appreciated but my main question is when I'm building the mould (gel coated & polyester fiberglass with 450 g/m CSM) how many layers of 450g CSM should I use in the mould?

I don't envisage using the mould a second time but as I have storage space available I would like it to be sturdy enough to keep it.