Nice to see that you are making some progress there Jake
I would imagine that 12.5" - 13" is more or less ideal for a dummy shock length.
One observation & being as you mention the front wheel tracking, are you using the original book length steering rack extensions ?
I believe that most folk find them too long ( I certainly did )
Looking at the picture, I can't see how much adjustment is left on the steering rack arms.
Looks as if you are making some great progress with your build