Bear in mind the hunter I core can run both regular irrigation wire and 2 wire from the same clock. so you dont need to run 2 wire from the get go.
You can just run your first four stations like you always do.
Hunter has some good online training webinars for installing and working on their 2 wire, so by the time you get to the point where you need to start installing two-wire you are already trained.
My vote, put in the I core, do your 4 zones normally and look up hunter 2 wire training... it's a no brainer.
In the meantime keep an eye out for a tech who already has two wire skills, or find someone, maybe here int he forum, willing to come out to your site, and sub a job while you work with him, to get more comfortable with it.
Didn't realize you could run both at the same time, good to know thanks.