Do not mount the reactor too firmly as there is a 60/40 chance you may need to tilt it to clear air out of a canister filter to get a restart. So make it something quick and easy. I like either velcro straps or there are also long plastic straps with slots for adjustments. A simple bungie strap can works well as it doesn't normally take much to hold them upright if they are designed with a flat bottom to set on the floor.
Point to question? I'm not sure I understand the design of that one with the CO2 entering so near the bottom as it is in total conflict with the Grigg's design. With the input so near the outlet, I would have assumed the bubbles would be blown out and into the tank.
But with that said, most of the stuff from Colin does work, so I will reserve judgement as I have not tried one like that.