The latest Totem Air creation, the "Totem Air Regulator Pro Swivel," is excellent and surprisingly reasonably priced.
The regulator's output pressure is adjustable from 500 to 800 psi. The preset outlet pressure can be modified by omitting washers. A regulator with one disk left in it will provide an output of roughly 450 to 500 psi. You will have 800 psi if you leave the regulator in its current state.
Additionally, the filling nipple's position can be flexibly adjusted. You can turn it on the adjustment wheel to your desired position after loosening three screw bolts. This will prevent the fill nipple to be positioned under the marker or in another undesireble position.