[LEAKYSEALS951]

In my peabrained experience with trying to clamp things together to redrill, even with the 1/2 thickness, I always end up walking the good holes in the direction of the bad hole to some extent. Always happens. It all depends on how precise it needs to be, If it really needs to be right, I would have a machinist move the holes with those bits and a damn good drill press/milling mount which would give him full control over the hole overbore direction. The harbor freight stuff can do it 1/2 arse, but with my crap it still walks a little off. A round metal file might not be such a bad idea.

edit- this is assuming you in your application you couldn't just clamp them all together and bore out everything to a larger hole size in a drill press.