First time start - no go

OK a few more comments

YOU CAN SAVE THE CAM if you are really into a "can of worms" here by REMOVING THE ROCKER GEAR. See? Easy LOL

You don't need to crank the engine to troubleshoot ignition, but it will be really handy to have two people. You can as I said earlier, disconnect the yellow start wire at the relay. This will keep the engine from cranking. Now, when you twist the key, you will get the same voltage/ current path situation for the ignition, as if it WERE cranking

Pull the dist. You can spin it by hand to test spark.

YOU DO NOT need to check valves physically. You can check for the correct firing stroke simply by compression at no1, OR check the valves. Either, or.

Timing. Just estimate. You can visualize the distance between to 10* marks, you can either guess "how far" you are from that, or measure between two, then measure that distance from the last one to obtain 20. ETC

Have you actually checked spark right out of the coil? Don't use the coil wire, as even it could be open. "Rig" a spark gap with a plug "opened up" etc