fish7777,
Sorry, I didn't know you had the QB 'ducer. For it I think you would need to use a switch. I've run a Quadra Beam through a 997c SI using the old TS2-W switch. There is an option for using the QB on the transducer selection menu. I used a towfish for the test run. The towfish helps reduce the effect of hull movement on the sonar capture.
click to enlarge >(http://limbatus.net/info/Towfishing/tm/picture-008.jpg) (http://limbatus.net/info/Towfishing/lg/picture-008.jpg)
The quad view output was better in color than it was on the 737, but I didn't see any advantage for my usage (saltwater ~ shallow ~ up to thirty feet deep). I could see the advantage at high speed with your shoot-through hull setup.
Darrell
PS ~ The current model switch is the TS3 ...
TS3 ~ Transducer Switch
New for 2011
This switch allows you to use two transducers on one depth sounder. The cable going to the depth finder is approximately 3.5 feet long and the two cables going to the transducers are approximately 24 inches long.