Sorry JimT, it's 4pm on Friday so my mind is elsewhere. Didn't full read your questions.
To answer your questions:
I tried the baskets and found that they were just annoying me more than anything else. I can make whatever size area for the coals I want with firebricks, and the bricks cost next to nothing. You can turn them, twist them, stack them to make the perfect area for coals for your application. Once the bricks heat up, they are also going to help maintain your temparature and use less fuel.
I also you fire bricks to set hot items, such as racks, chimneys, or pots on.
By putting down a layer of foil on the charcoal grate under the food, it will make cleaning easier (Learned that the hard way by bending an ash sweeper on my uncle's OTS). Also, the air from the bowl vents has nowhere to go but towards the fire.
I also usually place the vents for the lid over the food, which in my mind makes me think the hot air has to move over the food to get out. Now I have no proof of if this is a benefit, just makes me feel better.
Hope I somewhat answered your questions. Now back to figuring out what I should cook this weekend!