Spare ribs are generally a 3/2/1, Baby Back's mostly 2/2/1. Its all about the environment. If its cold,I would use those numbers if its hot I drop one off the second number. Its all about getting accustomed to your smoker.
Basically its 3 or 2 hours of smoke, then you add some steaming fluid Generally butter or oil, some sort of tenderizing fluid and I generally prefer apple vinegar, and some fluid for flavor like a juice.
When you roll 'em up, you are steaming the ribs. The steam really breaks down the connective tissues and fats making them fall apart tender. You don't really need to lock the meat up tight and hermetically seal it, actually more folks use butcher paper than foil.
Then the last one is to allow the meat juices to reconstitute. This is your time to visually see what your ribs need. If they are too tender, pull 'em, but what you want is for the ribs to be tender but still holding to the bone with a little "bite". This time will dry the ribs a little and its generally when people apply some glaze like BBQ sauce, honey, or an actual glaze you've made.
Thats it, 3/2/1 = smoke, steam then glaze.
BTW The reason I like apple cider on my initial rub and in my steam is my Pop who never did any of this always mopped with butter and applecider vinegar. The vinegar was to tenderize and the butter to brown and crisp.
Temperature? I never really worry about it. Every smoker has a sweet spot it likes to run. Find that sweet spot and then just calculate time, mine normally runs between 200 to about 240. Temperature is not an exact science when smoking, much like time. LOL The more variables you try to throw into the equation the more chance for nasty meat. Remember smoking is about low and slow. Your Pop and his Pop they had a campfire and a wooden out house, not to be confused with an outhouse. Or just a fire with a grate. Don't over think it, smile drink copious amount of hydrating beverages, tell lots of lies and enjoy the smoke.
Good luck with your ribs.
PS remember there are lots of ways to do smoke....