Re: Round or octagonal mast?
As Peter says, round makes it prettier. Also more value for showing off to your non-boat related friends. Most people find it amazing that a man can take a collection of sticks and then join them together so precisely and make'm all round and perfect. Even better if you don't tell them that it's not round initially, and they'll go round thinking you planed the curves perfectly so it all lined up when you glued it together..
Si Dieu n'existait pas, il faudrait l'inventer -- Voltaire