It would be nice if you could get your hands on the appropriate components for the vehicle instead of using whatever you have laying around.
Have you checked the ignition advance to ensure that it's working properly? Also the ignition timing while rotating the motor by hand.
The extended crank after it's been sitting makes me want you to check fuel pressure key on engine off. And also while at idle.
The broken vacuum line that you say is on the vacuum unit, where does this route to? Depending on the production year of the vehicle there are a few differnet vacuum diagrams.
edit> Thinking about this a little more this morning I had another question. The misfire occurs when going uphill. But, when not going uphill, can you get it to misfire simply by accelerating and getting the transmission to down-shift into the passing gear? If it only happens uphill then have when you get a moment have a look into the gastank and make sure that the pickup for the fuel pump is not all the way to the front of the tank. If it is it most likely is causeing the vehicle to starve itself and causing the misfire.
Then when the vehicle is back on level ground the fuel is now air-raided causing the a random misfire every ~10seconds or so.