Can you guys help clarify how to do the midpoint read for a basic putt like below....

When I use the book to help determine the angle... Do I use straight as the zero line- and if I'm standing at the red 'x'.... Just say that is approximately 45 deg from straight? So now I know I'm above the hole, take the difference between 60 and 30 and use that number for the 3%... 20' ring + delta of 15' + 20' x 2 to find the 30ft break?

My biggest confusion was on what angle I use?

Also, are there books with 45 angle numbers?