I know exactly what you are talking about schoppy, I just went through it myself with my 400, the hinges are difficult to adjust with the weight of the door on it! Because I'm such a life hack, here is my solution.
Start by wrapping a long ratchet strap through the door handle and completely around the boiler (use cardboard or rags to keep from scratching the paint with the metal portions of the stap) hook the ends of the strap together and loosely tighten the strap, place a small car scissor jack between the door and strap
( again use a softener) tighten the screw jack a bit so it will put pressure on the door inwards, now loosen the 4- 9/16 nuts that adjust the hinge side of the door, you should see the hinge adjustments move, unlatch the latch side and center the door on the jamb now take a few more turns on the screw jack, this will force the door onto the jamb, adjust your hinge and tighten them, dismantle the hack and move over to the latch side of the door. The latch side is a 3/4 inch acorn nut on each,loosen them and tap the bolts inward about 1/8 inch at a time, re tighten and try the latches, they should be tight enough to show some resistance without being hard to operate. With the doors all closed and the bypass open, fan operating you should not be able to hear any leakage around the door gasket. You will still have some residual liquid in the gasket that will drip out when the door is operated but it will subside and dry up after using the door a few times. The guys at the office can get you some spray bombs of the original color or if I have a chance perhaps I can find the paint color codes that I got from NAPA to paint the bus, it is an almost perfect match, best of luck and let us know how you make out!