I AuntieGin,
There has already been good advice to follow and it sounds like you are working towards success.
I always use the probe with my AQ and in briskets, I will use a separate thermometer in each brisket. I generally probe the thick part of the flat near the point/deckle end, but not in the point (too much fat). I sometimes use multiple thermo/probes in one brisket just to see also what the point is doing. Each brisket is different, so cook to temp, not time. What is that story about briskets from the left side of the steer... a Texan should know that one for sure.
LOL
It is not uncommon to see 230˚ when set to 225˚, especially in a new cooker (you could get plum sceered if you had a 055). Did you season with a pork shoulder or similar? After all your briskets, you should be there anyway.
I usually use about 3oz. wood for one whole brisket and 4oz for 2 whole briskets. Cherry and hickory are good. If using mesquite, I generally use equal amounts of apple with it. Have never got too bitter, but that is something of personal preference that only the cook and those at the table need to come to terms with.
Good luck, post more results.
Rob