Well I feel for you! I've been out today on my single-speed run-and-jump non-Douglas V-twin and easy starting is a must. Pity you're not a bit closer as I'd be happy to help.
From afar let me make a couple of suggestions.
1. Make sure you have compression on each cylinder. Pull the back wheel on the stand - you should have real resistance on each cylinder. (With the valves lifted the motor should turn over smoothly, with little "sticktion".)
2. Check the valve timing. At TDC on the non-firing stroke the exhaust valve should be just closing as the inlet is just opening. (Mark TDC on the flywheel with a texta pen for later)
3. Check for air leaks in the inlet manifold - at the joints with the cylinders and at the carby flange.
4. Check the fuel level in the carburettor. It should be just below the top of the main jet.
5. Check that the spark is about 35 degrees before TDC on full advance.
6. Decent clean spark plugs - Champion D16 or whatever.
7. Fresh petrol
8. OK. Tickle carby until it floods, magneto at almost fully advance, air lever closed, throttle lever 1/4 to 1/2 open, lift exhaust valves, push in preferred gear, once the motor is spinning drop valves.
9. Hey presto? Maybe not. Is there anyone experienced nearby who can help?