I would get max manifold vacuum all the while reducing your idle speed to the lowest stable hot idle speed in gear (which is what you will see stoplight to stoplight) or neutral if a stick, that you can achieve then reduce the INITIAL till the VACUUM drops 1 in hg and at that vacuum point your initial timing is ideal. if it will not crank when hot then reduce the INITIAL (1) degree & retry, then another degree if needed OR keep it where it was first at & wire in a NC momentary closed contact switch to the ign switch "ign2" terminal/circuit & push the button then get it cranking with the ign key then release the button while still cranking. As said get the FBO $22 plate, it is the best deal going by far & use it to set the total (initial+slots) & I would set the total to 35 with open chambered heads and 31 with mag heads which will be very close to ideal. I had 18 on a bone stock 80's 318 2bbl. holler what you end up with. EDIT then work with springs then plug in work with the can (if used). you want the springs to start advancing ~100-200 RPM above the hot in gear idle speed you have