There not that bad. Youve seen the pics of mine slammed, i was worried about them being lost but i actually love the look. The pics may look a bit deceiving but they dont look lost at all in the arches, just ask woody. Tbf tho, 10mm should be ok. Up to you of course tho dude, im just giving my opinion.
Also love the look of my car, but from some angles wheels look lost in wheel arches quite a lot. Can say the drowned wheels are only fault on the great appearance of the car...