Looks like a great medium - high ! Very cool looking! I love mediums!

It's pretty much what you see really. If the pattern to white ratio seems about 50%, then you got a medium. If it's mostly white with a few patches, then it's a high white. If it's mostly patterned with some white, it's low. There's various degrees, but it's all upto what you see. There's no test you can give to check the percentage unless you count the scales .