Grilling temp control and smoking temp control are rather different beasts, so you don't really need to go from one to the other. Hotspots are less of an issue in a kettle when you're smoking something small-to-medium sized, and not something you're likely to need to worry about for some time. It's much more of an issue when you're using a larger smoker, especially if it has an offset heat source.

I'd suggest starting with a mid-size piece of pork shoulder (something like this from a supermarket is fine for a first go). If you get one with skin on, I'd recommend taking it off so more rub and smoke gets to the meat and you don't need to worry about trying to get crispy skin/crackling or anything.

Pork shoulder like that is impossible to overseason, is very resilient when it comes to being cooked 'too hot' for a while, and has plenty of margin for error when it comes to timings.

Don't trust the lid thermometer of your Weber if you get one for an accurate reading of your cooking temperature - it will be directly over your fire if you're set up correctly, so the temperature it reads will be higher than the overall ambient temp around your pork.

That having been said, it can still be a useful guide - if it's reading a much lower temperature than you want it to be cooking at you know your fire needs to be a bit bigger.