You are liable to be disappointed about green LED output power. Since the human visual system is so sensitive to green, high radiance green LEDs haven't been much of a priority. Of course, some are brighter than others. If you're trying to achieve high visual brightness, have a look at units from Stanley, Sharp, Toshiba, all of whom have 'extra super bright' greens in the 'true green' and 'yellow green' parts of the spectrum. If you're generating a beam to be detected by Si photodetector, you'll get better coupling with yellow-green types from Betlux and HP. In any case, choosing a part with a narrow coverage angle will give higher intensity by concentrating the power.