Thanks for the replies! Maybe someone will chime in about choosing the subtests for the children.

I did come across this interesting link: http://www.gifteddevelopment.com/About_GDC/relevant.htm

The most interesting part to me was this:
"A Full Scale IQ score that averages gifted reasoning and average processing skills fails to identify either the giftedness or the relative weaknesses.

Test authors have wrongly assumed gifted children are fast processors. Some are very quick; others are reflective or perfectionistic, slowing their speed."

I wish I had heard of this center before I had my DD tested. I would have gone there.