I have a USP EXPERT with a Surefire X300 tac light. I saw the Lazermax Unimax rail mount lazer sight. I have a rail adapter on the HK to hold the light. I assume that the same rail can be used for the lazer, but will I need another to attach the light to the lazer? Which is better green or red? Is it worth it or do I just leave it be? What's your experience with lazers, good or bad?