Thank you to you all, you all are very kind and generous in sharing your experience and knowledge! Please keep the input coming, I am following this with interest. Slammie, it is interesting that you mentioned your DH's experience. I was probably tilting towards VS too, but was never tested. I was raised with poor math and science curriculum, in crowded classrooms. I ended up with perfect math grades at high school but there was no acceleration. It got fixed when I went to University but the first year was very rough. I ended up with rigorous math training, but I don't think I was an extended-norm-gifted type of kid, but one who worked very hard. I am unsure, these 99.9% kids, do they work extremely hard, or do things just look very easy to them at whatever level.

I have favorable impressions as well about Singapore Math so far. I think my DS also has the tendency to rush through to solutions, so it is good for slowing him down some and help him to look at the problems more carefully.