Strobe, and red, green, white position lights.
So, to answer the original question:
Your op limits require you to have the same lighting for night as normally certified aircraft. Those are:
1. red, green, white nav lights of prescribed brightness and field of view, and
2. approved "anti-collision lighting". This can be strobes or rotating beacon(s), again meeting brightness and field of view standards.
Where do builder install the "white" light?
I looked at a lot of RVs and never noticed white other than taxi/landing.
A better description for the tail position light would be clear. There is no requirement for white.
t.
What color is clear? I know what you mean, a clear window over a white bulb. But FAR23.1385ff use the word "white".
And in a later FAR (23.1397) even defines "white"
(c) Aviation white—
x is not less than 0.300 and not greater than 0.540;
y is not less than x−0.040 or y0−0.010, whichever is the smaller; and
y is not greater than x+0.020 nor 0.636−0.400x;
Where y 0 is the y coordinate of the Planckian radiator for the value of x considered.