lcopps wrote:

The white light must be at least 2-3 feet above the water. I forget which.

No, there is no height requirement by the USCG. According to
http://www.uscgboating.org/safety/fed_reqs/equ_nav.htm the only required
lighting for sailboats under 7 m in length and "vessels under oars" (I
think paddles and oars are considered synonymous by the USCG) is a white
flashlight or lantern which can be used to signal when necessary to avoid a
collision. Other lights, such as red/green side lights and a 360 white
light, may be displayed but are not required. I prefer to use a headlamp
as my white flashlight so I can use it to signal while still being able to
paddle.

Gary S. wrote:
In the US, any craft on the water at night is supposed to display the
standard basic lights, regardless of propulsion. Obviously the US
Coast Guard rules do not apply elsewhere, but your equivalent agency
may have similar policies.

There are many inexpensive lights available, which attach in a variety
of ways..

For radar, there are things called "corner reflectors" which do a fine
job of reflecting radar back to its source. These dramatically raise
your visibility on their radar for little cost and no power.