45 rpm Jomon Sizing - Help!

[Maharlika]

I just recieved a pair yesterday and it seems to be stretching fairly fast.. I'm normally a size 30, but I ordered the 31 because I was afraid that it would shrink. Obviously, they wont' shrink becuase they are ow ( one wash ) denims. If you've had experience with Jomons, do they stretch quite a bit? Should I exchange my pair for a size down or so? I would appreciate your feedback on this. Thank you!


http://www.pbase.com/rends/image/73550976.jpg