2. What are people using for the nuts to attach their foils to in the track systems? Can you get away with a threaded piece of flat stock that you'd normally screw into for a single fin or are the 8mm Chinook brass T-nuts essential? https://chinooksailing.com/index.php/wi ... t-8mm.html
For the trailing edge of CF masts what are the thickness/ profiles looking like? I know the very rear surface should be square but wondering what the thickness is on average-ish
Sorry, can't say about the trailing edge stuff, but from what I recall building windsurfers I think the mast box is virtually the same as the finbox. There are different options like how long they are, and whether there is a post off the other side, and also the mastbox has the slider hole at one end, but structurally I think they are the same. I should add that it's not like I have both in front of me right now, maybe a close side-by-side comparison would show otherwise, but certainly at first glance they seem the same. I can double check at the end of the day, I think I do have both kicking around somewhere.
As for the sliders, windsurfers used thin stainless sliders for a long time before the thicker brass ones came along. I think either would work and am not sure of the history of the change. It might be that high loading is not ideal on so few threads with the thin stainless slider. There must be a reason for the complete change over to the brass ones by the windsurfers.
As luck would have it, this week a guy just gave me an old mast box that he had kicking around. There is a subtle difference, the mastbox is maybe 2 mm less deep and might be 1mm narrower. BUT the mast box he gave me might be 15 years old. A deep brass nut fits in either one equally well. And squeezing them to try to close the slot they both are almost equally stiff, but the newer finbox is a bit stiffer (its thicker). For the way that two boxes would be used on a foilboard, even if current mast boxes are like the old one I have, I would expect no difference in how it would work for you.
Cool, looking forward to the food and stylin jacket. I just looked at what I have and compared o the website. The mastbox is still less deep, the non-ridged lower part on the side is taller on the finbox, just like mine.