That's great news. Must be like a great weight has been lifted from your shoulders.
One of the possible causes called out was an ignition problem. I certainly would not have thought about wrong spark plugs as it is a new build.
Were the plugs too short? How did you find it?
Consider updating the other threads you have opened so that others can learn.
With regards to your luck, I guess that depends on your view point. Yes, the project took a lot more re-work due to wasted effort. But no damage was done and it works now.
There is an oppertunity for learning here. It has to do with understanding the job and checking your work. At the risk of stating the obvious or starting a flame, if the timing procedures had been completely followed and more pictures taken during the work, then you would have known beyond all doubt
the motor was correctly timed. No wasted effort going back to re-check the timing.
I think you should pat yourself on the back as you have accomplished something that many talk/dream about but few actually do.