I laid mine on it back & made some spacers that were half the thickness o the seal I used, then placed to door on the on the spacers & made sure the alignment was good. Then I welded the hinges equidistant from the top & bottom of he door, seems to have worked for me.
I understand the spacers used for the gasket thickness...
I was more curious about the actual location of the hinges location...
The drawings are not indicating what that measurement should be
Thinking out load here but is I was to put them on the outer ends then the center would always be a concern for leakage...If I put the hinges to close together then I would be concerned that the outer edges were going to potentially leak...
I'm looking for a happy medium location
I put mine 5 1/2" from edge to grease nipple. the door seals very well with no leaks. Also, be sure to orient your hinges so you can lift off your door if need be. This will also aid in painting it when that time comes.
quick answer is it does not matter as long as one is near the top and one is near the bottom. the hinge position in orientation to the size of the door is not an issue. the thickness of the gasket is a bigger concern when it comes to hinge placement. as long as the door is flat and not bowed or twisted, you will be fine.