I made some runners this last fall, and there really is a wide range of thought on how to make them. I won't claim to know what is best, but I don't really think anyone does. I'd just wing it, if I was you. I'd go to Sarns Hardware and view their 30" set and then mimic them as best you can. The only things that really matter are that they are absolutely straight, and that the rocker is right. You won't get the rocker from a template either, so you may as well make them like you want and then put the rocker in afterwards.
After spending hours and hours on my runners, I'd suggest you just buy a set from Sarns, or a used local set. Where are you? There is a local guy that makes sarns knock-offs at a discount
http://www.davesmachining.com/Services.html
Check them out. If you are trying to save money by making your own, you may save a little especially if you have all the tools, but not too much.