Here's a quick jig to use for soldering 5-pin, 12mm wide LED strips. Models available for straight wiring, and left and right curves.
Note during upload of files - for some reason MakerWorld is unable to upload more than one (1) .stl file. I'm working on figuring out the issue and will upload the other two parts as soon as possible! In the meantime, the other files are available on Printables at the following link - [12 mm LED Strip Soldering Jig].