Wouldn’t applying to schools where the stats say admission is very likely be one way to yield good results without 10 applications?
My sons only applied to 2 boarding schools, because they were going to be day students. There is a third in the area that neither felt was a good fit. One of the schools was a “safety” so we were confident of admission. (We were confident for other reasons too, which are only particular to us). One son attended that safety and flourished, and the other attended the more famous/highly ranked school (and is flourishing 
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