OK guys here is some info. IMO until the questions mentioned above by cdixon are answered then you should consider GG as if they were HBG (I think they are a HBG variant). There is a place/use for HBG and it is explained well in the link below. The guy that wrote this article is one of the top PhD Fisheries Scientists in the country and has written studies on and experimented with HBG in deep south ponds.

http://msucares.com/pubs/publications/p1893.htm

In short they are an option in small ponds for a good high catch rate of nice HBG and small LMB (great for kids). They create a put and take fishery in that the HBG will have to be replaced over time. BG/CNBG and GG do not mix well as they compete and could result in a genetic mix that you might not want. If you read the link and still have questions then repost.