The SAFe Reference Guide is out.
The website has most everything you need, but it is hard to use and when printed in simplified mode doesn't contain the embedded pictures.
In our local Agile Meetup at Rally, Charles Bradley went through the 3 major methods for agile at scale - SAFe, LeSS, and Nexus
This book is a very useful even if you're not using SAFe, there is invaluable content in the book, including many pages on estimating.
So get the book SAFe , it's the latest in how to manage software development At Scale. LeSS has similar advice, Nexus not so more, you have to attend their classes.