If split in half both would be good high school programs. Summerville is nearly as large as Wando and West Ashley is not to far behind. Lexington is number 2 or 3 in the State in terms of size and Irmo and Spring Valley look like small colleges. I guess size does not give Summerville or West Ashley any advantage and only a little bit for Lexington, Irmo, and Spring Valley? Does Wando hold some secret other large schools cannot figure out?
Riverside was dominant at AA, AAA and now AAAA. As I understand, they are smaller than Most AAAA schools in the upstate but yet have a great quality program despite this imagined size disadvantage.
Academic Magnet does not appear to be hurt by small enrollment as they have walked the dog on larger schools at Viking Cup, Mauldin Cup and during the season the past three years. Hilton Head manages to win year in and year out with a small enrollment (they beat Wando in the past). They manage to defeat agree schools.
I am not citing examples from UpState because I am less familiar with schools up there. I only know what I read or hear. Maybe you should stick to the same philosophy and you might better enjoy your player's high school soccer experience.