if your making a kink rail or a down, deffinetly go tall. but if your just doing a flat rail, maybe a slight up, go for a low lip. the tall lip has sacking potential which nobody likes, so if you like your testicals, make a slope under the down/kink rail so u wont sack. hope this helps!
one time tanner hall did 2 marijuana's -illadelphlife
"a friend took two marijuanas at a party and over dosed, then he turned gay and caught AIDS " - *TACO-DOG*
"a girl grabbed my balls once and it scared me" .YMR.