I love using the polygon tool, but I found the hatching doesn't work will with home made pcb fabrication, so I go with a solid pour, your mileage may vary.
how are you running 20 white leds with only 5 volts ... sounds like a massively parallel array (bad idea). each string (of one led?) in your array will need a current limiting resistor to force current sharing, you can't just use one resistor.
One suggestion is to use a boost converter with an external switch, and aim for a higher output voltage. For example, if you take ten of your leds in series, you need Vf=33vdc and If=50ma to light them up, then take another ten and run that in parallel, totals being Vf=33vdc If=100ma. The MAX1522 supports Vout of up to 100vdc, and Iout of up to 1a. Now you have a mostly series array, and the benefit will be increased efficiency (two resistors instead of twenty) and more balanced light output, thanks to a constant current applied across the entire string.