Set the total advance, then go back and see what you have for advance at idle. Ideally, it'll be pretty close to what you had before, but the amount of advance (and when it comes in) is pretty spotty from distributor to distributor.
When you check your timing, do it at night or in a dark garage so you can really see what's going on. If the light seems to be misfiring sometimes, and the timing doesn't seem very steady on the 30* mark-- it's probably not your light. That's called "spark scatter" and I never saw it on any vehicle before I got hooked on ACVWs. That's not OK-- that's why these cars often run hot, "ping", and have flat spots. The spark timing is all over the map. It's worse when the advance starts-- if you watch your timing light from idle up to 3000 RPM, most times it's going to be unreadable along the way.
If you can read it at all, your distributor is better than most. If it's rock steady-- hold onto it and never let it go. Ever. OG German Bosch 010s (and the like) are reputed to be that steady, and they sell for $300+ each used over on theSamba. I can tell you from experience that no Brazilian or Mexican Bosch distributor will do that. East Asian copies? Please.
Couple the flakiness of the most widely used distributors with the fact that the points replacement modules most of us have been using for years are "less reliable" than we'd like to think they are (to put it kindly), and you have a messy, weak, scattered ignition system. Having something steady, strong, and reliable is worth the effort and expense. Everybody wants to spend the money for shiny new carbs, but the mysterious electrons under the red cap are presumed to be doing their magical 'lectrical thing. Out of sight is out of mind.
Distributors are lousy, points replacement modules are lousy, and coils are pretty lousy as well. All in all, it's the system time forgot. Motors got really big and really powerful. Carbs are the miracle of the mechanical age, and they are way, way more reliable than people think-- but somehow they always take the rap.
It's almost always spark. Even when it really, really seems like fuel it's spark. Even when you've driven (or trailered) you car through a biblical thunderstorm, and you're sure (SURE, I tell you) that you've got water in your float bowls or in your idle circuit-- it's spark. When you're a newbie, it's spark. When you're way too experienced to get sucked in, it's spark.
A car with a plugged idle jet won't idle well, but it'll clear out when it comes on the mains. Drive it hard enough, and you might not even realize it. A misfiring engine stumbles and bucks and farts and backfires. 95% of fuel problems are spark.
That's why I was droning on and on about crank-fire. Not because it's easy, or because everybody does it-- but because it's the final solution, the end of all the spark nonsense we all endure all the time. A Black Box gets you 50% of the way there, but it's not really the right 50%. Some alternative crank-based pickup (I've been looking at the Moroso flying magnet system for V8s) would be much, much better.
Good luck. Forewarned is forearmed.