> how does pbryant rig his red on green?
The COLREGs require that the vertical separation of the red light over the green light be 1 meter (39.4 inches). This vertical separation requirement is, I believe, the reason no commercial product is sold that conforms to the Rule 25(c) requirements.
There is an exception: if the vessel is less than 12 meters, the separation can be smaller and proportional to a 12 meter vessel. So an 8 meter Ariel could have a vertical separation of 8/12 meter: 0.67 meter (26.4 inches). Two lights separated by 1 meter will appear to the naked eye as two distinct lights at a distance of one nautical mile (according to the COLREGs).
My installation looks just like the illustration in the COLREGs (attached below). I have a red all-around light at he masthead, and four green navigation lights mounted on the mast at the uppermost level of my mainsail with the first reef taken in (I rarely sail with the main unreefed since it balances my 100% jib with the first reef taken in). My 100% jib also does not extend all the way up to the masthead. The four green navigation lights are mounted so two face forward and two aft on each side of the mast, forming a 360 degree arc.
If someone wanted to produce a commercial product, it would have to be on a pole with the red all-around light at the top.