I in the 'no kit needed' camp. Save yourself some money, go to lowes or Home Depot buy a 1" dowel and a cheap level: done. I've been using the ol' piece of plastic baling twine (easy to see) with a weight on the end to check cant (with a level on the rifle). If you haven't turned many bolts and can't tell when one is tight enough or going to strip; buy a torque wrench (in/lb).
It's also very dependent on your set up, with a 1piece base it's pretty difficult to misalign the rings. The last scope I mounted had a bubble level in it (konus M30). What about the old leupold standard bases with windage adjustment? Aren't those stressing the tube? I can't think of a single modern scope that won't have enough internal adjustment for any slight errors you may make!
The people who say you must mount them the 'professional way' with a kit must be way better shooters than I am.
My shooting buddy always takes his guns to a local store to get his scopes professionally mounted and laser bore sighted (I just look down the bore); last time we both went out to sight in new setups he was way further off initially than I was.
