[sanddrag]

300 Watts in 8 square feet? All I can say is it must be high noon on a clear day at the equator, and even then, good luck. In this circumstance, if I'm not mistaken, the sun irradiates approximately 1000 watts per square meter on the surface of the Earth. You have about 0.74 square meters, so assuming 100% efficiency, that's a maximum of 740 Watts. A higher end PV panel might get you a 20% efficiency. so, you'd be looking at closer to 150 Watts best case scenario.

Move the panel out of the atmosphere (into space) and you'll get about 36% more power.

Anyhow, what Al said: what is the height available? I was assuming minimal height. If there's no height limit, you can do a lot more.