I haven't had any issues. All my fuses are mounted to the kit at their respected locations. I followed/still following his other projects "snow leopard" on the fj boards.
FJ Dual Battery Cable Set
This also has a PDF of the cable lengths. His build thread on the board has some good pics and...
I used Herculiner. Seems to be holdin. Up. When i make a final version I'm real happy with, I'll probably spend the extra cash to have the line-xd. But happy with the bedliner.