The Sigs use the same mounting pattern but are a little longer. So if you have a blast sheid on your mount that goes right to the front of your RTS2 it might be an issue. And maybe I was mistaken about the RTS2 I was looking at but It seemed damn bright.
The Sig's are definitly everything I would want in an optic though, big glass and the dot is bright enough that you would never need anything brighter.