Yes direct sun, South exposure, on churches, universities, a Frank Loyd
Right and other high quality homes in the chicago area ive done. 750 was
a usual base cost for a trashed out old Oak or Walnut door. Unlesss it
is a Marine product, forget it. The key issue is it must have
flexibility and UV stability, Polys are to hard, possibly even Marine
Poly. Contact a high quality boat maker, boat service yard, or boating
supply that handles wood boats, not just fiberglass at a local shop.
Aplication is critical as wood needs to be bare, cool, and not to be
heated in direct sun for many hours, often evening is best after sun has
passed for aplication. Sure you pay for P&L, but a quart can do most
doors and more than pay you back in its longevity.