Hey Marc
When I was going through initial start up after rebuild I ran into a similar problem. My wires ended up being off 1 position as someone else mentioned earlier in the thread. I went through the same though process you're going through - compression, spark, fuel, head scratch - repeat. When I finally got the wires in the right spot the timing wasn't very critical for the first start. If you're within 10/15deg either way it will start, or at very least cough and sputter for you.
I agree that a big squirt of gas down the throat or filling the bowl and pumping a fair amount will get you the initial start where fuel is concerned.
To Keith's point if you have a valve hanging open it won't be happy about it but all other things correct it will start on 5 without too much challenge. If you have multiple jugs not holding pressure it probably won't go. You can put your finger over the plug hole and spin it over for a shade tree compression test (press it in there hard) It will blow your finger out of it's got enough compression. If you can hold the pressure with your finger chances are it's too low.
So all those words and I got nothing new for you. My process would look something like this.
Be sure battery is full and starter is spinng engine quickly.
Stick your finger in each plug hole and spin it over, if they all blow your finger off assume valves and rings are good enough to start.
Ensure you have a nice bright spark - good coil and condenser, points clean and operating ok, plug wires not frayed, clean cap and rotor. Spin it over several revolutions while watching the spark to be sure it's not intermittent.
Double check that your TDC timing mark on the front pulley is near the pointer. Ensure piston #1 is at TDC, rotor is pointed at the #1 plug post, wires are on correctly and correct firing order, plug gaps are close. (#6 will be in same position as 1, if you can't get that plug out weld a nut to it (get it good and hot when you weld it on then spray it with a little water to cool it down quickly for some thermal shock) and back it out).
Dump a tablespoon or 2 of gas down the yap and try again.
Cuss (maybe ingest another adult beverage)
One additional thought. Please keep in mind I got no idea what I'm doing so everything in my post is pretty questionable advice.