[ajstrider]

1. I never flip on the UDS
2. I like to lay flat unless I need more room, then I use a rib rack
3. You will improve your design and build another
4. I like to start with butts, they are hard to mess up

Assuming your eight lid holes are evenly spread out, that should help alleviate any possible hot spots, this is the way I made mine and I prefer it over the one large exhaust. I am about to play around with adding a water pan to mine, but it is just experimenting. I would not worry about a diffuser plate unless you just wanted to tinker more.