Metz 60 series
Most of my wedding work has been done with a Mamiya C330 and prism finder, so I have some experience with carting heavy stuff around.
My best results have been with a Metz 60 CT1 and a Metz 60 CT2. I use one flash at or near the camera, and where possible, the other on a light stand nearby, triggered by a slave.
I have a modified left hand bracket (with trigger) for the C330 that allows me to mount the Metz bracket to it - the combination is large, but not as heavy as you might expect, due to the fact that the battery pack is separate.
The bracket I use also works with the RB 67, but I don't know whether it works with the RZ 67.
The Metz 60 series flashes are great. They've got lots of power for bounce flash operation, flexible adjustments, really accurate automatic functions and when used with dryfit batteries they give quick recycling and lots of flashes per charge.
I can put two flashheads, two battery packs, an extra charger and a couple of charge plugs in a relatively small case, and still have room for cords, flash slaves and other accessories.
Hope this helps.
Matt