I am also wedding photographer here in Austria
have tested and used many different straps and systems
and my favourite one is a System made in USA called Spiderholsterhttp://www.spiderholster.com/dual-camera-system.html
It is not easy to find any store here in Austria which sells the Spiderholster
So I ordered it in Germany http://www.enjoyyourcamera.com/Spider-Holster:.:95.html
The spider is the best system for Wedding Photography I have ever used
It’s not cheap but worth every cent
Give it a try
The second best system is the BlackRapid RS DR-1 Double Camera Straphttp://www.blackrapid.com/products/double
the Problem with it is that it hangs all the time on your shoulders so it is heavy when you are using huge lenses like the EF200 2.0 on a EOS1Ds3 and on the other strap the second EOS1Ds3 ...
It also interferes with your Photo Backpack
Have tailored another version based on the Black-Rapid design that does not interfere with my Photo Backpack
but when using that self-made "Black Rapid" I found the SpiderHolster
The SpiderHolster is the perfect solution for me. Currently I do not use my self-made BlackRapid anymore nor the buyed one...
Hope that helps to find your system