I was just reading a thing about Peter Criss' autobiography, in which he offers the information that the KISS cock size ranking went Ace > Peter > Paul > Gene. That sounds about right to me.
And on further reflection, I'd say
Ringo > Paul > John > George
Adam > the other guy > Edge > Bono
Meg > Jack
Jones > Page > Plant > Bonham
Ron > Keef > Charlie >>>>>>>>>>> Mick
No need to continue the thread, I just wanted to get it out there