Your right about the 20 degrees, my mistake. I took a look around while getting the link, guess the 70 stuck in my head. I've got some hooked up to a Tiny13, Knight-rider style, that comes on at night (well about 30-40 minutes before, need to adjust that sometime...). They can be seen easy across the street, even about a block and a half down the street. Then trees block the view. Guessing well over one hundred feet from the side, but maybe not as brightly lit as your gym.
What exactly are you trying to do? It's tough to help, if we can only guess. The high wattage emitters need a heatsink or they burn out quickly. Also a series resistor isn't the best current limiter for these. I don't think PCB copper would move the heat away quick enough.