Sonar for the front????

I have a Hummingbird 797c with the transducer on the transom, and I love it!!
I'm now trying to decide what to put on the front with a trolling motor mounted transducer. My troll motor is a Minnkota Riptide with CP and AP. I looked at mounting kits for the tranducer and it appears to be a stainless compresson ring and a bracket.

My first question is do these kits work? Stay in place?

Next what unit? I realy like the Hummingbird 727 or the 717. 640 vx 320 pixles.
Any other sonar I might want to look at??

Thanks in advance:)

Don't know about Humminbird's TM mount but Lowrance's work just fine with no problems. They look pretty much alike so I can't imagine any problem.