I don't really reply on dot speed to read per say. Just I make sure I have initial 5ft and last 5 ft break read carefully. I also keep alot of mental notes.
There many holes where mental notes will be much more important than any green reading.
Just remember faster the greens the sharper the break since you hit the ball slower. If u hit with authority (to cut on some break) and miss, expect 5fters back.
-wgticon