Yea I hear ya on the peace of mind. Maybe you could have someone whip up a spacer out of delrin. I'd probably also buy one or a few if you do. Aluminum would be neat because you could get it anodized a really bright color to keep from losing it, but it would probably be too expensive to be worth it.
Edit: Post up in the airsmiths section and you should get a response. You might need to send out your gun and an A1 barrel if you cant get the measurements yourself.