That's not right. The cage size doesn't matter as long as it's operating within limits. GS has a max cassette of 46t and 10t difference for 1x. For 2x it's 42t max cassette with 10t difference still. SGS has the same spec but the main difference being the max front difference is 18t to accommodate 3x drive train. The only reason to ever be using SGS is if you want to run a triple. This is strictly for MTB as the road stuff works a little different since it's not technically designed for 1x.