even though I think that it is correct to wear it any way you want to...I would still avoid any type of drastic angling similar to how modern Berets are worn..Maybe square on the head with a little tilt to it, or pulled forward...remember that bonnet of the period wasn't just a "fashion statement" as much as it was a functional article of clothing, usually worn to not only keep the head warm, but the sun and rain off! I think pulled forward is a little more Jacobity
Cheers,
Chad