How's the exact number relevant?! There's no way to read the attitude to the 10th of a degree on your PFD. Let alone determine if the struts are compressed, semi-compressed or not compressed.
Don't you think it's more relevant to look at factors that influence the tail clearance? Significant crosswind, tailwind, high gross weight, (threats), high rotation rate, early rotation, incorrect performance calculation, incorrect oleo inflation (errors) etc. And try to eliminate them? I.e. use correct take off rotation techniques, consider using a higher flap setting or higher thrust setting when the above factors are present?