If you're feeling spry, buy yourself some bulb terminals (mushroom heads) and make one continuous wire from bulb to switch, or wherever you want it to go. No butt splices required! If you absolutely have to do a butt splice, get the connectors that are the heat shrink style. Pretty weather proof.
Last time I got bulb terminals, I got them from Ron Francis in a 10 pack? If you going to do a lot of them, I'm sure electronic supply houses like Mouser and such, will have them in bulk.
