Most guys that make rockers don't understand ratios. Most guys that use them don't either.we were forced years ago to buy an expensive computerized spring dyno due to one manufacturers inconsistency.
so we actually run every spring we use on all the engines we build through it and get their actual solid height.
some springs are held to a pretty tight tolerance. some not as much, but typically they bind shorter than the box says, so they are not going to go solid if you use the box specs. you can always make soft jaws for a vise and bind them in the vise and measure.
our typical distance from bind on bracket stuff is .090 ish from measured max lift with checkers. Without spin data, you are guessing at it if you factor in deflection, because most if not all of the deflection comes back dynamically when its running. And thats not factoring in loft. Which is why we use actual measured lift with checkers. Its amazing how much most rockers are over advertised ratio.