The last time I needed a new grill, I bought a four burner gas model, just so that I could control the temperature adequately for slow cooking.
I generally grill my ribs for 12 to 18 hours.
I typically wrap them in heavy duty foil, along with a marinade such as Stubbs, with the bone side up. I put the foil on a cookie sheet (that's to contain the juice if the foil leaks), and cook about five hours at about 160 - 170 deg. To get maintain a temp that low on a warm summer day is when you need the four burners - you only turn on one burner, and you adjust the flame to maintain that temperature. At this time the meat should be starting to fall off the bones.
Then I open the foil, turn the ribs over and finish them off with the foil open. I baste with the juice inside the foil, and add start adding bbq sauce if I'm going that route. I have a smoker box that I put some wood chips in and I place the over the flame to generate some smoke. I also put a large pan of water inside the grill to keep up the moisture.
To get a nice thick layer of sticky bbq sauce you need to be adding bbq sauce for about two hours. You put brush it on, then as it stiffens you brush on more, and keep doing that until you get the coating that you want. Temperature control is critical to do this right. If you get it too hot (more than than about 170 degrees), the sugar in the bbq sauce will caramelize and form a hard coating on the ribs. Too cool and the bbq sauce doesn't stiffen. Again, in my experience you can't get that degree of temperature control with anything less than a four-burner grill.
Did I mention that being able to control temperature is critical?????
The other thing is that you learn what works by trial and error. "What works" means the techniques that are easiest, which sauces give you the best combination of flavor and the grilling characteristics that you want.