you can use #8 thwn type but the vd will be about 5% but i ran with my figures i keep my vd to lower numbers i came up with # 6 size because you did not figured the ballast loss so i add little more leeway on it the VD is 2.7% [3.2 v]
if the building power supply have 120/240 or 120/208 i will try to run higher voltage if possible to keep the VD more lower
this what i came up if wired for 240 volts with the same number of fixures for 500 feet run my figures show can use #12 wire. the same thing if wired for 277 volts too can use #12 also but i will suggest is check the design lay out to see the best run with least amout of wires if nessecary.
i am sure most parking lot lumiaires useally have mutitap ballast you can wire on higher voltage if the sisuation called for.
if more question you can drop the line here
Merci , Marc
Pas de problme,il marche n'est-ce pas?"(No problem, it works doesn't it?)