Hello Joseph,
Sorry for my late answer, but I enjoyed sailing in Croatia with a conventional sailboat;-)
I do not feel competent enough to give any advice, my method is try and error, when in doubt: Add one layer...
I will try to write something about my ongoing conversion in the boat shed, as Paul asked me to do so. Today I realized that the mast I purchased (tempered flag pole) was slightly damaged by a visitor with his car. Not to take any risk, I will have to buy a new one, which may be thicker than my 150mm/5mm flagpole. Besides the cost I already had this in mind and I am currently laminating in a 200mm/5mm sleeve, that would allow to house a mast of up to 170mm diam. Still I have not decided yet, if I will have a mast laying device, which would ease any futher alterations concerning the rigging.
As basic material I used 16mm AW100 plywood for the basement and the partners, , the partner rings I screwed with inox screws and glued them together from half rings, which is a lot of additional labour. If you have someone nearby to cut out the rings f.e. with a CNC machine, that would probably save quite some hours of effort. also a cone could be easily shaped, which eases the later laminating.
As I could place my new mast foreward enough to save the front hatch, I also used the front hatch support and reinforced it by 3 layers of plywood.
As lateral reinforcement for the deck partners I glued in two "beams" of plywood 100 X 16 which I reinforced by another layer of 70X16 plywood. Laminating the whole construction with 5 layers of 450gr/m² triaxial glass fabrice. The same I did from the lower deck partner to the bow (rather to the anchor chest).
On deck 4 layers of plywood make the base for the upper partner, laminated with 10 layers of both bidirectional and triaxial fabrice.
The keel bottom is made of 4 layers plywood, the most difficult for me was to get the bottom partner half way horizontal, though my 200mm/5mm sleeve will allow some adjustment play to get the mast straight.