A 10x will work with the 200 AB and 220 SMK well. If you want a slightly slower twist for better use with a variety of 180's, the 11x will work well also for the 220 SMK and 200 AB. You will NOT stabilize the 240 SMK with the 11x though.
Long range shooting is a process that ends with a result. Once you start to focus on the result (how bad your last shot was, how big the group is going to be, what your buck will score, what your match score is, what place you are in...) then you loose the capacity to focus on the process.