Just a smidgin off your inquiry, < a quarter bubble?
Loading fiber wads, i.e., the old Ljutic 'monowads'or others, in plastic cases normally "stretches" the case mouth, making them essentially a one time reloading proposition .. at least that has been my routine experience. I have not ever detected any increased leading from waxed vs non-waxed wads, but that is my experience only. I do not see any downside to using them, case life aside. Some good patterns can be attained within skeet range, it gets regular 'iffy' quick beyond that, again just my experience. I think it was Fransis Sell that claimed tight patterns w/card or fiber wads at long ranges. I never could.