The stock is actually stuck in customs in Sweden, but that's another long story I can't go into right now!
That rider is approx. 1/2" wide from memory. I may be able to dig out the email with the details of the original order for the bag and that might say which version it is. I'm pretty sure it was the most common 3/8" spread but I can't be 100% certain.
How urgently do you need a bag? We move all the stuff out of storage around April 24th so I can get to it again then.