GUE teaches a sidemount class that's highly specialized and not regularly scheduled in their general course offerings. The prerequisite is Cave 2 and a "need to know" request for learning the techniques of passing through overhead restrictions within the DIR paradigm. Otherwise as a business, training & product model, and in contrast to UTD, they see no reason to currently market a sidemount course or advertise any additional equipment besides the Halcyon Contour sidemount harness for general recreational open water scuba.
For doubles sidemount, they utilize
Lola cylinder valves with a flexible crossbar interconnection routing in front of the diver at chest level between the two cylinders.