Transducer and graph interchangeable?

Probably a dumb question but say I get a 9” with S and DI and a 7” with S, DI, and SI are the transducers interchangeable?

I’m looking at the Lowrance Hook2 7 Tripleshot and Hook2 9 Splitshot. Any experience with these units?

Also, with the Garmin Striker units, if I graph the lake at one level and it goes up or down is there some way of offsetting the water depth on the maps or do I need to redraw it? If I redraw at the new depth does it replace what I had or is it a new map?

The triple shot and split shot probably won’t be interchangeable, because triple shot has side imaging and the double shot does not. If you’re comparing the 7” and 9” of the same technology (double to double or triple to triple) I believe the only difference is the screen size.

I have the Hook2 5 and I’m pretty sure if I wanted to upgrade to the Hook2 7 all I would need is do is plug and go, but the transducer would be the same. Not true if I wanted to go from downscan to downscan and side scan.

I don’t have any experience with Garmin products.

That’s what I figured. Would have been too easy.

I went with the Hook deal at Academy. They’re on sale right now. 7” Tripleshot and 9” Splitshot both for $900. $300 off.