Identifying tartans?

[enemix]

Inspired by the pictures of NewYorkBen in the X-kilt tutorial I went to a fabric store in town and found these two that I liked. Not sure yet which one to use (first) in a black X-kilt.

Anyone knows what tartans they are? With the help of Google I found that the right one is probably Stewart Black, the left one I have no idea. Maybe not even a real tartan?



Second question: I know very little about restrictions on using tartans, but would anyone really object to that usage? Were I to make a proper tartan kilt I would of course do some more research to not step on any toes.