Setting up Pontoon with SI and DI ??

Wondering if any of you folks that fish out of a pontoon boat have any suggestions for what you have found to be the best location and setup for mounting the locator and transducer.
I am rigging my 28' pontoon, and being that it's 28 ft. I'm a little concerned that mounting the transducer to the stern will be so far behind me from where I fish that it will not be as useful as it should be, but of course I need something back there so when I'm running across the lake with the outboard. And the other unit up front off of the TM but not sure which one to put where, I will be installing a Humminbird 587 DI which I've had NIB box since 2011, but also looking to purchase a Humminbird SI Combo unit. Any help/suggestion will be appreciated or if you have any photos of your setup please share.

Unless you are familiar with Si sonar I would recommend starting with it on the back and put the DI unit up front.

Thanks for your help Greg. I have not purchased the SI unit yet, was planning on getting the Ulterra TM and a OnixNT unit, but it seems both of those are having some problems, at least according to the guys at the Broken Arrow Bass Pro. They said the Onix units that they had were sent back and are not stocking any Onix's at this time. Have you heard news on Onix issues?

No I have not.