I find that if you cook a large roast at 350degrees, it will carry creep up between 10-20 degrees. That said, I typically pull a bottom round for deli meat at 105 to get a nice rare/med rare.
For a prime rib, I pull at 105 as well. I let these roasts rest at least 30 minutes - no foil tent.
2013 Stumps Classic - Delivered 4/15/13
Large BGE - Rescued 2012
2010 WSM 22.5"
2010 Weber genesis gas grill
Rescued 22.5 Weber One-touch gold
BBQ Guru CyberQ
2011 Built UDS - Retired