I use a torque wrench for a lot of things when doing maintenance at home, but have not used them for rack bolts.

I have a little different system than most, but it works for me:
-I don't use locktight on any of my bolts.
-I apply a thin coating of grease to all my bolts. I believe a clean, lubricated bolt can be installed tighter than a dirty, gummed up with locktight bolt using the same force. Initial installations using locktight are different, but once the locktight dries on the threads reinstallation is a different story.
-Bolts are tightened to torque specs, or in the case of rack bolts, until they are "snug".
-"Snugness" varies depending if the steel bolt is going into an aluminum or steel frame/fork.
-On tours rack bolts are checked about every 3 to 7 days. this is the interval that I usually do cleaning and preventative maintenance on tours.

I've never had a bolt problem.