Ah Boy is strong-willed. I am sure he will survive in any school. Why don't you let him make the decision? It will be better for your relationship with him and it is part and parcel of him growing up.
I totally agree with ngl2010. If you don't mind me saying, your worries n concerns are unfounded. I can see yr Ah Boy has his strengths which are equally good with kor kor, so its best not to compare. Ah Boy wont like it too.
U are blessed with 2 good sons!!!!