I would like to report success in installing the new HUB, daisy chaining the the new together with the original hub and running the Yamaha 6' device cable into the electronics tub. It was not easy, that I can say for sure.
As noted the original HUB YAMAHA - COMMAND LINK MULTI HUB ASSEMBLY - 6Y8-81920-01-00 was behind the gauge panel. I used a 1ft daisy chain bus cable to the new HUB and moved over the terminator.
I then needed to run the 6' Yamaha device cable from the new hub behind the gauge panel to the electronics tub.
I first loosened the breaker panel inside the cabin as suggested. I let it hang. Then I needed to pull up the wire sleeve that covered the existing wiring into the electronics tub. This was slow work here. The reason why I had to pull up the cable sleeve completely into the tub is so I could fish the Yamaha 6' connector end through the opening down to the electrical panel area. Without pulling the sleeve up I could not pass the connector through the sleeve nor through the opening. I redressed the cable sleeve and made sure I pulled the sleeve all the way down, back to where it was originally. Take note of this step, it helps dress the cables when your done.
The next challenge was getting the other end of the Yamaha 6' device cable to the hub behind the gauges. On this 33 Express there is a opening on the STBD side of the gauge panel area. You need a wire snake, nylon is preferred or something stiff. I started the snake at the gauges and after 4 tries I finally got it to behind the breaker panel. DONE!!! Whooohooo. It appeared to look like the snake was either getting down between the "head" bulkhead or going straight across toward the binnacle.
Lesson learned
1. Need two people....(Well I did)
2. Need a snake
3. Need minimum of 6' for Yamaha device cable to make that run from gauge area to Electronics tub.
4. Need only one j1939 Garmin to Yamaha Device cable. Even if you have two Gamins
5. This forum is awesome. The advice here was spot on and gave me confidence to DYI this project
Two great TIPs:
1. Remove Electrical Panel (removal of tub not required)
2. Remove Pin to ram in electronics tub and hang cover by bungie to reach the back of your electronics.
Thanks Again to everyone who replied.
Boating season is 4 weeks away