The " 40 to 140 in 4 " guideline is explained in this forum's intro. Just a note to Addertooth...The bug Clostridium Botulinum are sensitive to Oxygen and although not killed, will not multiply. Oxygen has no effect on the Toxins produced.
The " Minimum " USDA recommended Smoking Temperature is 225°F. There should not be any Restaurants smoking meat below that temp. At home or at Competitions, you and anybody else can do what they want. In this situation, Injecting and smoking at temps below 225, there is always a risk of contaminating the interior. But it is important to understand, " nothing will happen unless something goes wrong! " If the smoke goes along without a hitch, the extra hour or so to get the IT to 140°, smoking at 200°F, is nothing to worry about. BUT...If you fall asleep, the smoker dies and the meat sits at a Bacteria Love Fest' temp of 80° to 100°F for a few hours...Make sure you have good Medical and Life Insurance if you plan to eat the meat. You can reduce if not eliminate the risk of pushing surface bacteria into the meat by Washing the meat and drying with Paper Towel ( you never know what is on the dish towel hanging next to the sink), being super careful that no meat juices contact the surrounding area. Make sure You and your work area are clean, then rub the exterior of the meat with a Rub containing Salt and/or Sugar, followed by injecting a Sterile solution....JJ