Yongnuo triggers: two camera, three flash setup

[TiCoyote]

So here's the wedding setup I'm going for:
Canon 5D, on camera Metz 50-AF1 with eTTL, two off camera 50-AF1s, 24-70mm f/2.8L.

Canon 50D, no flash on camera, still triggering the two off camera lights, 100mm f/2.

This allows me to do a lot of medium and full shots with the 5D, great exposure, and I can do some more artsy closeup candids with the 50D, playing with the lights and the shadows.

Right now, I have everything above, (except I only have two Metzes. the third is a "passable" Sunpak flash). But how to trigger?

I have a set of the RF-602 TX and RX. I need a setup that has a trigger for each camera, and a receiver for two of the flashes. A few months ago, I ordered a second RF-602 set, but when they came, I found that it was actually a RF-600. The difference is that the transmitter does not have the PC-Sync port. It's a problem because I put one flash in the 5D's hot shoe, and then I plug the TX into the flash sync port on the camera. No sync port, no good. I thought this was an older model, and I had been sent the wrong thing. I sent it back to the seller (eBay hassle, a story for another post).

Then I was going to order a new set, when I found out about the RF-603. This has two big advantages: 1. It's a TX/RX and 2. It runs on AAAs instead of the CR2 battery.

So I bought four units. Just got them in the mail, and guess what: the PC sync port can be used to trigger a flash, but not to trigger the device to transmit. So when I plug it into the PC port on my camera, nothing happens.

So what to do? Get another set of RF-602s? Guess what, the RF-600 is the newer model. For some reason, they took out the PC-Sync port. So I could find an old set of the 602s online, but then I'm relying on discontinued technology. Or I could put the RF-600 on the 50D, since it only transmits to the flash, but it doesn't have a flash on it. Although it is possible to put the 603 on the camera, and then the flash on top of that, you lose the eTTL.

Well, now I've ordered a FC-681 cable. It has a foot and a hot shoe on one end, and a hot shoe on the other end with a locking cold foot. I'm fairly certain that it does eTTL pass-through, and I know that I get eTTL on the other end. Hopefully, I can put one end on the camera's hot shoe, and put the flash on top of that. Then I can put the 603 at the other end of the cable, and keep it in my pocket. I know that I could get the same goal with PocketWizards, but this setup is $90 for four TX/RX units and a sync cable. I'll let you know how it goes. If anyone has any advice, I'm all ears.