I agree Bilje.......not all succulents like exactly the same conditions..
As to how damp is damp and how dry is dry........just how long IS a piece of string anyway ?
Twice the length from the middle to the end...apparently
I think the key is to have a very gritty growing medium for aeoniums. That way, you can water more freely but excess water will get away from roots.
I think Fairy's "string" theory sounds logical. If you are tall Verdun, your string will be longer I think than the average
Perlite or grit...........if you grow in containers, grit is better as they get so top heavy the extra weight can help.
If you click on this thread and scroll down http://www.gardenersworld.com/forum/talkback/visit-the-old-vicarage-gardens-east-ruston---friday-5th-june/719339.html you'll see Wonky's photo of the aeoniums at The Old Vicarage Gardens East Ruston in Norfolk. They're outside all year round, protected in the winter from the bitter north-east winds by some great shelter belt planting