I think it depends upon which association you practice with as to how the kyu/mon grading system goes, but by and large I think Judo is much the same as any other MA in its grading. sadly in the UK almost all Judo is sport Judo and promotion through the grades is to some extent reliant upon proficiency in competition as well as knowledge of the art. For self defence i would recommend Ju jutsu/aiki jutsu as a better bet, although that is only my opinion [IMG]http://www.fightingarts.com/forums/ubb/smile.gif[/IMG]
From your description of the technique I have absolutely no idea what it is. It doesn't sound like any Judo technique I have ever seen, particularly the bit about knee to groin!! I would think that would be an illegal move in Judo, to put it mildly [IMG]http://www.fightingarts.com/forums/ubb/biggrin.gif[/IMG]
Budo