898 si or 958 di

Here is the problem, I have a 798c at the console and a 757 on the troller. I want to get a bigger screen and wondered which would be the best way to go. Put a 898c si at the console and move the 798c si upfront or go with a 858 or 958 di up front. You spend 80% of your time at the troller looking for structure and fish there so I think that having the bigger screen up front for the Di that you found with the Si makes more sense. Dosent the dedicated new Di have better picture quality that the si/di units. After you Si scan them you can mark them on both units which I can do now with the 757. Any thoughts would be appreciated

I like the bigger screen for SI. 898 at console. If 757 has gps keep 798 and 757 up front.

I want the DI up front just think keeping the 798 at the consule might be the best. It would be the cheapest or at least a lot bigger screen up front for the same money.