T9 is no real prob as far as era's are concerned.certainly on the 757we work on 400 miles which gives you a lot of France and Spain.T16 is another thing with at one point only the fields on Cape Finesterre as options -STG ,Vigo,La Coruna etc (AVS just makes it).On a dark and dirty night you may ponder on which of these is even open never mind all being affected by the same weather system.Better still to ponder it in the crew room and re-file domestic or T9 if you have worries.It's called airmanship.FWIW on a straw poll among our trainers I raised the "if STG is closed is it ETOPS?"question and got a different answer from each of them! I would therefore refer you to my previous statement re airmanship.