Hi Wade
Yes I did invest in a twin probe digital thermometer, it was a cheap-ish one from Amazon but seems to be pretty reliable and it talks to my phone so I can monitor from indoors too. It seems that the lid thermometer isn't massively different though, just a little either way.
The ribs went well. I got a great meaty set from the butcher, when I got them out of the bag I was worried they were a bit too meaty, they even had some large flappy bits overhanging the last rib which I trimmed off and made some more burnt ends (reserved for the pitmaster as a reward ?). I did have to trim them myself but I watched a few you tube clips and seemed to do it ok. The membrane came off fairly easily too. Sadly no photo of the finished ribs as by the time I went to get the camera the family had eaten all but 2 ribs!!! I take that as a good sign, I was pleased as they even had a decent smoke ring (first time I've noticed it on my meat). I used the 3-2-1 method but the last hour was more like an hour and a half/two hours as the sauce took longer to set than I was expecting (I used firefly Texas sauce). The meat didn't fall completely off the bone but came of easily with a pull so was pleased with that.
We are having another gathering next weekend and when asked the vote went for more burnt ends so I put in another order with the butcher, he even knew it was me calling this time. He did ask me when I was going to be brave enough to order a brisket though lol! Maybe next time!