concave will hold your feet in well when sliding. I would widen it by 1 inch if i were you, i think the dervish is really skinny and kind of wierd, but i that may just be bacuase i have larger feet. If you want to to sliding and commuting, think about a 1/4 or 1/2" drop. This will make it easier to lock your feet in for slides and downhill shennangians, and beacuse your doing a topmount it will bring you closer to the ground making it easier to push. if you want a commuter, your looking at larger wheels, and with a straight topmount i think you would be to far off the ground and in an awkward pushing postion. just my 2 cents