....sepia??? lol btw. most autos wont go for 70 days. they usually take 70 days flowering plus 2-3 weeks natural veg stage.
If you're going to use 500w why not just get a 250w HPS and have less heat, less energy usage and more lumens? HIDs get about 110-115 lumens per watt while CFLs only get like 60-80. At 500 watts you're gonna have to deal with a good bit of heat and will still have to keep the cfls fairly close. Have fun in euro. I've never been before, but I heard it's pretty awesome. Every year my college does this "travel across europe" thing.
HIDs produce a decent amount of heat, but so do 500 watts of CFLs, probably more. A 250w HID puts out around 28000-33000 lumens. CFLs really aren't that great for large grows. How many lumens total do you have per square feet? Remember lumen output that is listed on the packaging is per square feet. Brettsog just switched from CFLs to a 250w HPS, you should ask him. https://www.rollitup.org/cfl-fluorescent-lighting/527144-second-grow-ww-bagseed-big.html
Unless you've tested them already in grow area that seems like it's going to get pretty hot. My 42w's raise the temp a good bit in my bin. If you have tested them temps in your grow area, what are the temps normally.