in my experiences, yields do not suffer one bit from light rails. i have no numbers for you, but an experienced grower i know has done a comparison.
3k watt (1 hps, 2x mh) vs 1k watts on a light rail, and had 4 grams less on the rail..
it may take some dialing in as far as the delay at the end of the rails. i have mine set to 30 seconds.
would stick to your exact growing methods as far as everything else goes. lollipopping included.