I do the same thing with lining damper up with 0º on the pointer, then line up #1 on the rotor/cap relation. Some find #1 compression, set the damper mark to whatever they want their initial advance to be (i.e. say you want 15º initial, usually a reasonable amount for a street SBC), then line up #1 on cap/rotor. This insures almost 100% that initial timing is where you want. The only thing you need to cap off when setting timing is whatever port the advance canister hose goes to on the carb (the fitting on the carb itself), capping the advance canister fitting itself will do nothing.
On a parts note, I had an ACCEL Super Coil:
This ran fine on the 305 in the Malibu before I pulled it for the 350 I built. Put everything back together and it wouldn't fire. Put a stock coil in and it fired on the first cylinder. If you have another coil laying around give it a shot