I just installed a whole set of strings in the back of my pickup's topper around the windows - just used HitLights for the supplies . If you are good at soldering it's the best way to go - do not use heavy or low-strand wire , use fine-stranded 20ga or so . On almost all the weather resistant types of strings there is a coating of clear vinyl that protects the electronics and chips - it has to be very carefully removed to put the connectors on correctly and it takes some practice . If you try to cut the vinyl off and nick that copper backing strip it will tear off or crack and lose conductivity - so be really careful . I use scissors to cut the tape at the break lines in the strip , carefully cut the vinyl down at a slight angle about 3/32" away from the led chip and just gently peel the top vinyl coating off . This exposes the copper strip connection points so you can put a small dot of solder on each conductor , then solder on the wires ....finish it with some good quality NHT or similar dual-wall vinyl shrink boot.
Sarge