I have only had the lights for about 2 weeks now and have not received my CO2 system yet, so I can't really comment on the pearling. Plants are still adjusting to the brighter light.
As far as the light coverage goes they are wide enough to cover my entire tank without any dark spots. The lenses are convex and do a decent job of spreading the light. I only have them about 5 inches above the water level and they look good to me.
They do look pretty cool. I would love to hear about the growth once the Co2 is in place.