5 months give or take? sometimes quicker. March/april when the lineup is complete is usually when they sell out. But last year they had a capacity increase so maybe it'll take longer now.
slipknot doesn't take rocket science to figure out. I'm more talking about the 2X metallica mainly since they haven't announced anything nearby. or correct leaks in the past?
I'm sure they're really good bands and have a lot of fans, but these bands are just not something I like to listen to. Especially considering that 115 euro can go towards 3 or more indoor shows of bands that I do like.