no idea where the timing is.

The vacuum advance should be connected to ported vacuum, not manifold vacuum, so you'll want to reattach the hose to the small nipple that only has vacuum when you open the throttle. 16 BTDC is a bit much but if it doesn't ping, it may work for you. I'd back it off to 10 and see if you can get that manifold vacuum reading up. It should be over 16 inches at idle. You may have a vacuum leak somewhere or a lumpier cam than you think. When I do a tune-up, I do it in this order.....Valve adjustment (if applicable) compression test, new plugs, new points/condenser (if applicable) cap, rotor, wires if needed, set timing and idle speed/mixture (you may have to back and forth on this until both are correct). Timing is with the vacuum advance hose disconnected and at proper idle speed. I also test the PCV valve for function at this time too. Replace air cleaner element if necessary. Do a road test.