Tim ... I have a Lowrance Elite 5 DSI unit on a 16' Procraft ... and I mounted the tdx on the trolling motor. Now, I do have a 2d H-bird in the dash, with the tdx shooting thru the hull, but I can still see the E5DSI good enough to use the GPS mapping screen when on full plane.

If it were my boat/unit .... I'd put it where it was going to be used the most. That would be at the trolling motor. I'd set the Garmin to run horizontal screens, and use the whole screen on Down View when sitting up front ... and the whole screen on 2d when trolling from the console. Reason being ... you get a picture image from the down view, so you can immediately identify what comes on the screen. And I'd use the 2d sonar screen when trolling, so that even though the trolling motor isn't pointing straight ahead, you're still getting the same image from the 2d sonar cone. You'd have to leave your TM down, of course, but trolling speed shouldn't hurt it none.

The only time I'd use the split horizontal screen (down view & 2d sonar) is if I was trying to teach myself what the 2d sonar images "really" are. I don't have 2d sonar on my E5DSI, and don't miss it one bit ... even after using only 2d sonar units since back in the 1970's.

That's my ... if it's worth that

... cp