You need to work one problem at a time. Disregard the coolant for now if it is boiling all the coolant out on the ground. If this is the case, clean the block and radiator first.
The octane scale is only for fine tuning after you get the timing really close. You really need a timing light for this. I too have never seen much success with setting timing with a vacuum gauge. If thats all you have, then make the best of it. Set for highest reading then back off a few degrees using the octane meter.
You are still on ported vacuum if it rises as you speed up the engine, manifold vacuum will fall as soon as you crack open the throttle. Be sure to check the vacuum advance for movement, it should rotate the distributor as you rev the engine.
Who knows what is going on in your block, why is vinegar in there? Why not use a actual block and coolant cleaner? If you see bubbles all the time, I would suspect the vinegar is eating away the crude. Exhaust leaks to the coolant would be blowing coolant out at a pretty steady rate. Add a vent hose to the overflow tube and submerge the end of the hose in a bucket of water. If the exhaust is leaking to coolant, you will a increase of bubbles the faster you run the engine. It will stop as soon as you shut it off.
