Note - Atlantis Gate is custom made full ring so about 1/3 of the chevrons aren't tv show accurate, rest are. Looks great regardless. Also casting line across bottom portion that I can't remove.
Measurements
SG1 - outer diameter 11-5/8" (29.5cm), mirror diameter 8-11/16" (22.1cm), depth 5/8" (1.6cm)
SGA - outer diameter 11-1/4" (28.6), mirror diameter 8-1/8" (20.6cm), depth .5/8" (1.6cm)
Weight is approx 1.25lbs (560 grams)