You should have no problems with Cat-6 or Cat-7....they are essentially the same conductors with a tighter twist/braid allowing for reliably higher data tranfer rates.
thanks for those informations. So I think we will go for Cat7, then the sound-guys might use the same cables. Rental-company with light & sound department ;-)
we have a supplier here in germany for snakes and cables with ethercon etc... And because the sound-department would prefer CAT7 Snakes and cables(some digital console need CAT7) it would be nice to have just one type of cable that both departments can use.