Telling one kitten from the other

The two girls have been identifiable from their head markings for a long time. "Wiggle" has has a central wiggly stripe, "Star" has a broader diamond shape in the same place. Now the boys are becoming easier to tell apart. Not only is one bigger than the other, but he has a short sleek coat like his mother - shorter than other Abys I've had. In comparison the smaller boy looks quite fluffy. The kittens have free run of the house now while we are around, except for the kitchen, and interact with the other cats. Cold weather seems to have brought on a resurgence of suckling, but the attraction of a hot drink seems understandable. This isn't an easy house to keep warm. They've checked out the Christmas tree, but aren't overly interested.