Ignition not fuel delivery? Pre he

Either I misread timing before or something moved internally with timing chain or? during transmission removal/replacement but now I have discovered the following:
With the timing mark on the crankshaft at TDC the ignition mark for #1 on the distributor was way past the magnet, like almost one cylinder worth. counterclockwise.
So I moved the crankshaft to 10 degrees before TDC then loosened and advanced the distributor… I now have the #1 mark exactly on the magnet mark.
In theory I may have discovered the issue of no start or very low idle, no power, backfires, etc. that I’ve queried about before.
But before I put cap&wires back together I wonder about this: I will not be able to retard the timing at all. The vernier adjustment is maxed out Lots of advance available. Should I worry about this or might there be another tooth between the two still available to me? The distributor did not move much and its a big pain to locate the allen bolts as many of you know… I did not pull it out only lifted it with the bolts undone. Any attempt to retard the distributor in its current location covers the allen bolts. Rotor about ten o’clock with the vacuum advance pointing at firewall. Seems right, I am just concerned about lack of future adjust-ability.
Thanks in advance and for the earlier help.
.PS .I took Haynes advice and have Spark plugs at .035. I cant imagine it not starting because of this but should i go ahead and put at .025 like its supposed and recommended to be? Or is that just an HE issue?

We had one report a few years back of a V12 losing all the teeth on the jackshaft sprocket, so the distributor was free to jump time by a chain tooth at a time. It was an odd thing to happen once; typically such a thing would either never happen or by now we’d have heard of it a bunch of times. In any case, I suppose worn teeth on that sprocket is one thing to be wary of.

IIRC, .035 was the recommended gap for the pre-H.E.

Hi Cyderman
In kirbys book it mentions the ideal positioning of the vernier and the Allen key bolts. In my opinion the vernier needs to be in the middle so you will have timing adjustment available when you put a timing light on the engine.
Ideally the Allen key bolts are about central in the slots.
It is a little fiddly to get it just right as you have to allow for the slight rotation of the rotor as the shaft slides onto the jackshaft.
To me it sounds as if you may be one tooth out on the distributor.

Thanks, if it moves again, assuming it ever did,I’ll know what to investigate.

OK , I must be suffering from V-12 overload. At least its one less do-over.

Thanks from the other side of the world. What a far flung group of apparent masochists we are! I hope to get it driving so i can see what the reward is all about.
I will see if I can split the difference before I button it up. I also will see if i have an original reed trigger board and if not maybe my power to the hall board is poor or the connections are loose.
Thanks again.
ps I noticed the on line advice on fastening the board mention nylon screws. Pretty sure mine are metallic.Could that be an issue handed down to me? I also saw one very small washer to fit with the screws on top of the the mounting pads. Are they necessary if not all there?