Look at a 100 normals there is a massive variation even in the 'normal' I don't think it possible to set breed standards like dogs. To be honest the stupidest thing I have seen in a long time is a friend has a boxer that due to changing laws and his own preference it has a full tail and unmodified ears and it was rejected from a show because it wasn't a standard... I hope that this NEVER enters into the reptile breeders!