Honestly, I don’t get why Andover, Groton, and Choate are so interesting to you and St. Andrews is not. From everything I have heard about it St. Andrews is an incredibly amazing school. Dig deep and make sure you are not chasing the name brand when it comes to Andover, Groton, etc. Also realize that while those schools may offer courses you are interested in it’s not possible to take all the electives you want while still fitting in the courses you are required to take and all the EC’s you may want to do. My guess is that any great boarding school will have plenty of selection for you.