Ok, update. I can alter Target Value and the Thresh holds and I can set the default for my priority field, but I can't make changes to Target Unit, Trigger Date and Target Type. I can just replace all the default fields with my own hand made fields, that works fine. If I make a Target Unit v2 field and add all the same options then I can make all the adjustments I want, but that doesn't seem right.
I have figured it out.