Bill,
I don't have any pics but I can explain. The tip tanks I bought had moulded in pylons which I drilled for two servo mounting screws.

Matching holes were drilled through the wing tips and then the hole in the top surface of the wing was opened out to take a piece of plastic tube. This tube is a tight sliding fit on the screw heads so I don't loose the screws.
Between the screws is a servo plug and socket, one half in the underside of the wingtip and the other half in the pylon.
I cut the tip off the tank until the 1/2" reflector was a perfect fit and glued it in. The reflector is then just covered in Sellotape crystal tape and the LED is a push fit from behind.
The LED's run off the Rx batteries and are switched through a RC switch on a "Y" lead to the U/C system, so the lights are on whenever the wheels are down.
Regards,
John.