I don't know how the green laser would fare up against a green background. My only experience with them is here in the desert, we have the hand held ones that take two AAA batteries. They're bright as heck at night, visible out to three hundred meters easily, but during the daytime it drops down dramatically, if you know where to look for it, you can see it out to about 75 meters, but its very difficult to pick out, and thats on a tan background.
I hope that helps you a little bit, my advice would be to get the most powerful, brightest one you can afford/ get your hands on. if you do shoose to go that route, while lasers have a dramatic effect on iraqi drivers, as well as the M9 pistol, I personally feel that for actual shooting goes, a good red dot scope would do you better, faster on target and all that. just my .02.