Get both the Crack and SB. But focus on the Crack and take tour time.
Soldering on PCB's is quite different than the hardwiring in the Crack.
Take your time and study (youtube..) before beginning.
Simple tips:
* Adjustable iron? I aim for 440-450 Celcius.
* Always apply a bit of solder to the iron tip. Otherwise you can't transfer the heat
* If you solder something tiny to something thick, then only apply heat to the thick item (The LED's in the kit are easy to kill..)
* Don't apply too much solder. The joint should not look like a bubble/blob.
* Follow the guide to the point! It is really great