Just my opinion, but for a larger diameter cooking chamber, I'd go with the longer stem. My brother has my dad's old offset, which is heavily built, but the cooking chamber is pretty small. I think the grate in that cooker is only 16" wide by 30" long. I think the stem on that cooker is probably 2.5" and it seems to read just fine. Temp control on this old offset has been great since I got big brother the baffle plates to evenly distribute the heat and smoke. He also got a charcoal basket that has helped extend his cook time.