I have 2 GGs, one Gray and the other Golden, both are around 13". When I first got them (at 12") and put them in the 100G, the Gray one virtually tore the golden into pcs. But after awhile, when, they both got transferred to the 1,000G, they are now the best of friends.
Also have not noticed any interaction between any of the GGs and my 8" Motoro, been with me for 3 weeks now.