It's actually quite simple to check without factory data. At the crank, the engine sees 10 degrees or so BTDC at idle speed. At 3000-3200 RPM there should be 34-36 degrees at the crank. There it stays all the way to whatever redline you choose. With a primary and secondary spring there will be a small bump or flat spot in the curve as one gives way to the other, and all you can really change is the rate at which each achieves its full travel.
A sick distributor probably has some spark scatter, resulting from a worn cam or bushings. It may also have sticky weights and not retard or advance reliably. Spin it on a distributor machine and measure the angular variation, and plot the curve. If it runs out about 12-14 degrees on the distributor, all is well. The vacuum retard function is brutally simple and simply takes out about 7-10 degrees of advance under conditions of low manifold pressure. Don't even connect it.