A newbie question…I’m sold on Armstrong foils but as a new foiler I’m going to progress through boards quickly (I hope!) so it seems best to buy a secondhand starter circa 125 litre. I’ve spent a half-hour searching but I cannot find anything that tells me whether Armstrong masts work on other board brands eg Slingshot which I see a lot of in San Francisco. (I messaged the company earlier today but haven’t heard back. This was the nearest I found…but no mention of Armstrong https://www.mackiteboarding.com/news/-hydrofoil-boards-bolt-patterns-and-compatibility/ )
I figured out the answer - “90mm dual track” - is the standard eg https://www.mackiteboarding.com/ride-engine-foil-track-box/. They do vary by length.