Well here's what I think. The less ribs you are cooking at a time the harder it is. On large scales it works well due to a few factors... the retainment of moisture and heat from the other ribs is one factor --- the inefficency of the actual apparatus you cook on is actually a benefit to an extent. HOWEVER - the more insulated the gear and the success goes up, the heat and moisture retainment taking the place of the mounds of meat.
On your set up follow the rules, when your ribs are about to weep, make sure you have very little unignited fuel left - this does not mean to let the fire go out but just be sure you stir the fire and make sure there is no black charcoal or wood. Then, when the ribs are fully weeping as shown in the video, damper it down... even the stacks and let it ride down in temp for a while without opening it. How long, I cannot tell you because my setup is different from yours.
Another thing, when you glance and confirm the weep is occurring, wait a few minutes before you damper because you want to be dampering from an operating temp (the one you had before you opened it) not an opening temp (which is MUCH lower).
