After giving the sail options due consideration, I decided on ordering the Sail Rite kit. That project will give me something to do while this cold winter drags on into spring.
As for that lesson: we are all very much aware of the adage, "Measure twice, cut once."
It applies to boat building, woodworking of all sorts, many other arts and crafts and life in general.
Two weeks ago I ran the numbers for the birdsmouth staves for each of the spars (yard, boom, main mast and mizzen mast). I carefully recorded the dimensions in my notebook and put it aside until it warms up enough to actually work in the shop. Yesterday I reviewed those numbers and found an error (in my dimensions for the mail mast) so glaring (off by more than 50%!) I was shocked I hadn't seen it two weeks ago.
I'll be re-checking all of those numbers a few more times before I cut any staves for the spars...