10x for the Pre-Rosat section of the Artificial Humans Arc so that Gero's statement about the humans, Gohan and Piccolo makes slightly more sense, and a 2.5x for Gotenks due to general scaling and the lack of seeming like a dozen fold increase against Evil Boo make it seem nowhere near warranting a 50x multiplier. Other than that, I stick with 50x for the rest of the manga, since even being as minimal as possible, I'd find it hard to not have the Base Saiyans leagues above #17/18 by the time of the Boo Arc, with the Mighty Mask fight suggesting they aren't apart by some several times gap (unless you believe the costume made that much of a difference).