Keith
I think your big problem was you had people to feed at a time certain and you were anxious. I can well understand that because it invariablly happens to me. Best advise might be to plan on completing 2 hrs ahead of eating time and then use foil and an ice chest to hold. However, I know, it's more fun for everyone to "check the grill and watch you take it off."
Reread MM in the cooking section. Meat should be added when the cooker is assembled. With water it will take some serious time to get up to the 225., but it will gradually be rising as the coals light rather than falling when you put the cold meat on at 225. If you think about, using standard, you put the meat on when it comes down to around 300 so it then falls into the 225 range.
Good luck, remember, we all learning something with each cook.
Paul