Smoking is an adventure, along the way there are SO many options, it's hard to choose.
Sauce is one of those. Sure, you can put it on early and you'll get a certain type of rib, but don't put any rub on nor worry about what smoke because it won't get any because of the sauce.
Not good, not bad, just a different adventure.
The fun of BBQ for me is learning the steps along the way.
Layers of flavor.
Smoke
Rub
Mops/bastes
Finishing sauces
Techniques
All so many things.
The only way to learn it, is to do it.
Don't try to sort it out in advance. BBQ is about doing, cooking, eating, learning your mistakes and making changes and trying new ones.
Some work, some don't.
If you have a couple of racks, experiment. maybe you actually want more sauce on your ribs. Maybe you don't want any (my preference, sauce on the side).
Now get out there, get cookin' and report back to us.
Oh, #1, take good notes, it's your best investment for improving with any cooker.