you know I'm going to say go ahead and prune it. CFL's don't have much penetrating power as it is and I feel that it's far more important to keep an even canopy than it is under HID lighting.

This way you it becomes easy to keep the lights as close to ALL your plants or all areas of your single plant. Creating more bud growth to the entire footprint as opposed to one cola that is taller than the rest of the canopy.