The way that I set the spacing is to weld the hinge on the box good and the tack it on the door then put the gasket in place and close the door. The tack weld will bend and then the spacing will be almost perfect. The steel has a memory so it will spring open like it's too tight BUT the gasket will also shrink when heated. Kind of a trade off.
Its Si-intistic, Jack!
One lovely UDS
Shanaynay--Custom Home Built Smoker on Wheels-SOLD!!