I have a 2005 Orca that needs its seat post clamp replaced. It appears to be a non-standard clamp size. I tried 28.6 and 30.7 and neither worked. I could get one from Orbea, but I prefer the clamps with the barrel to keep from over tightening. Has anyone found an after-market clamp that works with the older Orcas? I'd like to find a light one if possible.