This torque wrench works well:
http://www.midwayusa.com/product/718...ProductFinding
There are a number of levels around and I do not know if any one works better than the next. Tiny little bubble levels can only show if any surface is close to square with another surface with a tiny little bubble level on it.
I have read the comment on the internet that "my scope is bad due to cross hairs that are canted by one degree" from fellows that place way too much faith in their ability to center a bubble.