Hi Nic;

I am not a good instructor on layout systems and you probably need some personal instruction rather than just from a book, but I wanted to mention for you to look for information on the double cut scribe system and to say it is common in old frames with irregular timbers to flatten the timber with an axe or adz, just at the joints and then scribing whicch is probably easier than scribing to a round surface.

Fox Maple School of traditional building has connections with Costa Rica, but I do not know if any more workshops are planned.

Jim

In another thread Our Barns pointed out Edward Shaw's "Civil Architecture" which is one of the first books to discusses both scribe rule (using the double cut method) and square rule.

google this: "civil architecture" shaw

Jim