I got Seyfried's book many years ago which really helped me when I was making some bino's out of a couple of 4" refractors. See link - and have a good laugh at the price!! There are some great tips and lots of info that is clearly explained in the book. My project was comparatively simple as I only had a pair of moveable mirrors to collimate with rather than trying to move pairs of porro prisms or eccentric rings. One of the best tips in the book was to hold your head back several inches from the bino's while lining up on a distant tree/post/building - any collimation errors become really obvious.
https://www.amazon.com/Choosing-using-repairing-binoculars-Seyfried/dp/0934639019?¤cyCode=AUD