Everyone has their own preference. Doubt it matters so long as you don't line the gaps up. But I'm anal so I clock them all. If I'm installing a piston on the driver's side I put the top ring at about 11 o'clock, 2nd ring at about 7 o'clock, oil ring spacer at 3 o'clock, and the oil rings at 1 o'clock and 5 o'clock. This is assuming that 12 o'clock is pointing straight up (towards the intake manifold). In actuality, I think of the gap positions in terms of degrees rather than on a clock system, but it would be too difficult to explain that in written form. Basically, think of the top ring gap being at 30 degrees above the centerline of the piston, oriented to the front (probably closer to 10:30 rather than 11 o'clock). Hopefully you get the point..