I don't know if an R - 4 will accept a long yoke or a banjo fitting. But if you have Dacor tank valves, they have what amounts to an HP port on them that you can run your SPG off of. The port is only live when you open the valve so installing the SPG is a piece of cake. I'll be diving one of my R-4's this weekend and I'll check and see if a banjo will work with it.