Flipper and 70Chevelle pretty much hit the nail on the head.
For baby backs, if you can maintain a steady 225-235 degrees then a 5 total hour smoke will yield fall off the bone ribs. One tip I can pass on while using a grill is do not open the lid, fore go any basting. Most grills will drop up to 100 degrees when you open them. Of the 5 hours, I prefer 2.5, 1.5, 1. That's 2.5 hours of smoking (I use hickory) unfoiled, 1.5 hours of foil and 1 hour unfoiled with no smoke. Sometimes with grills, you may have to do 3-2-1 to get fall of bone due to it being difficult to maintaining temps.
I have found ribs with sauce (wet ribs) with fall off the bone texture is the biggest crowd pleaser. 98% of people will think it's the best ribs they've ever had. Most people have maybe been to a real BBQ joint a few times in their live and consider chiles baby back ribs the best BBQ they've ever had. The last 2% are BBQ purists. I can tell you if you make fall off the bone ribs this weekend for your guests then a competition style rib the following weekend and ask your guest which they liked better, odds are 98% will like the fall off the bone better.
To make my best ribs, after removing the membrane I brush melted butter all over them. The butter assist with basting the meat thus keeping it moist, it also bring a great flavor to the party. Once the butter hardens, usually 30sec, I put on the dry rub (my receipt is under rubs). My ribs immediately go into the smoker. I've tried letting it sit for two days and also tried marinating. Through blind taste testing, couldn't tell a difference. This gives the luxury of turning on the smoker, go buy the ribs and by the time I get back and prep them the smokers up to temp. At the end, I tried adding the sauce at the last 30mins, doesn't do it for me. I add sauce once the ribs are out of the smoker and all cut up and. For the sauce, add your favorite bottled sauce and add honey to it. 1/4 cup of honey to every 1cup of BBQ sauce. This effectively turns your smoky sauce into a sweet glaze that's very high gloss. I cut up the ribs, then brush on sauce all over. If you want to caramelize the sauce and warm up the ribs a tad, move your oven rack to the top position and on your oven broiler to high and watch close. After 30-60seconds you see the glaze start to bubble, that's you que to remove them.
Hope this helps. I made near 100 racks of ribs now and those are my very best, if using spareribs I do the same thing only use 3-2-1 method. I don't mean to brag but people have begged me to make these ribs, again, these are people are not BBQ purists.
Shoulders doing ok, thanks for asking. No pain unless I move it. While sleeping is a different story.