the mount shouldn't be too hard a flat plate attached to the block over the water pump to attach the charger to, and a pair of tabs for the alternator.making it line up shouldn't be too hard, I have a spare motor to use for mock-up and fabrication, and since I have the non AC stuff to throw on it, I can even mount the serp pulleys on the spare block to make sure it all works perfectly, and get the proper belt for it as well.
as for the calipers, I have a good set of dial calipers(again, used to be my dads) and have found that good measurements between bolt holes is really easy, all you have to do is measure between the left, or right sides of the holes(assuming they are the same diameter) and that measurement is the same as between the centers.