Alright matey, my tuppence for you:
I have a UDS the same size as your Webber but I have two shelves on it.
Using a rib rack like this:
http://www.gardenxl.com/proq-smoker-rib ... tAodiTEAtQI can cook 7 racks per shelf, it holds five racks of ribs, then I lean one extra rack on the end and one extra down one side, that all fits nicely on our size food grill.
I'll often do 30-40 full racks of Bookers ribs in a sitting, I normally cook them for 2 hours on the smoker at 120c, then remove, wrap in foil and bang them in the oven for another 2 hours at 120c. After that I remove, unfoil, lightly coat the top of the racks in BBQ, sprinkle rub over the top and bang them back on the smoker for 15 - 30 mins to firm up if they are to be eaten then and there.
When I do them for consumption at a later date, for people at work or where people have ordered food for parties, I will cook them the same, 2 hours on the smoker, 2 hours in the oven wrapped in foil I will pull them from the oven at the end of the cook, bang them in the freezer for 30 - 60 mins to bring the temp down before putting in the fridge then when they have chilled I'll vacuum pack them (or if I'm not selling them as I'm just taking them down the road to my mates to be cooked the next day I just re-wrap in fresh foil) and I pass them on with a sachet of BBQ sauce and a sachet of rub.
Then I give the following instructions on reheating:
For the ribs (if you have frozen them let them defrost in the fridge overnight first):
Preheat oven to 120c
Remove the ribs from the vacuum packaging, wrap them in foil and place in the oven, bone side down.
Cook for 45 mins in the oven
Leaving the oven on, take the ribs from the oven and take them out of the foil (CAUTION, they will be hot and steam will escape)
Cut the edge off the sauce sachet and squeeze a little sauce over the top of the ribs and spread it around, you just want to cover the top of the ribs in a thin film of the sauce (don’t drown them in the sauce – YET )
Sprinkle about half of the powder in the other sachet over the top of the ribs where you have just spread the BBQ sauce
Put back in the oven, bone side down, unwrapped for 10-15 mins
Remove ribs, try one without any extra sauce, try one with extra sauce, make a decision on which you prefer, get tucked in and get sauce all over your chops and the shirt your wearing
Hope this helps