In my short time smoking (since I found this place) i've gone from a general obsession re: temps to a general confidence that using those doneness indicators the OP mentions is all that's necessary.
When I fire up the WSM, it usually finds somewhere between 250-300. Wherever it lands, that's what I go with.
I have 2 cheap wireless probes that I use less and less. I've scrapped the plan to add probe grommets to my stickburner and WSM.
I think back on all the great Q made w/ a freaking hole in the ground filled w/ embers and sometimes think how ridiculous it is (for me) to feel the need to use even a plain ol dial therm. (ymmv)
Reading so many posts here stating "it's done when it's done" has chilled me out re: being anal about temps/probes/times.