I have used grain of wheat for years but I am moving to LED's as they are alot better
LED's need to have a resistor fitted to them so that they don't burn out, you can get them already pre-fitted
The easiest way I found to do things is that if you put 2 peices of brass rod in the superstructure and then wire these as positive and negative
then wire the LED's to it makes it easier for wiring
to fit them drill a small hole in the superstructure and glue them into place
if the LED is out side you can disguise the wiring as Pipe work solder them onto brass rod to make longer if needed
I hope this makes some sense