We've all heard about the the proper angle for pinball machines, from the low end of 3.5 degrees for EM all the way up to a faster 7 degrees plus for new machines.
Do you have a rule of thumb you follow? Of course each machine has a sweet spot, but there's gotta' be a baseline? Not every machine has recommendations in the manual, what do you do then? Feel it out, go with similar recommendations for the same era?
Is the golden number really 6.5 across the board in your opinion regardless of generation?