You can take a set of jumper cables and double up the ground to an additional place on the block. Yes you can jump straight to the solenoid. Yes, 12 volts is OK to the starter. If you have not succeeded by now, loosen the distributor lock down and rotate it, while starting, in the direction the rotor is turning. The amount will be small if you are in the ball park. Be ready for a possible backfire, if you are advanced too much. An engine will pull a small carb fire back into the engine, if you can stay on the starter. I do not think you have any mechanical binding. It sounds like a new engine, getting enough voltage and the spark right.
let us know how you do.
good luck,
If you want to set the timing before trying the above, put hot to the ignition, with the dist cap off, the engine set at TDC or 6* past, rotor pointing toward #1 plug wire terminal on the cap, turn the dist until the points break and arc. Snug the dist down enough to keep it from moving, loose enough to turn. Your timing should be real close.