Initial Setup Questions on HDS units

Alright, so I just purchased a brand new Lowe Stinger 175 last week. The boat came standard with a Lowrance X4 that is built into the console on the boat. I went out and purchased the Lowrance HDS 5 and Structure Scan in a package deal. I am looking at purchasing another HDS unit either the 7 or 8. My question is how do y'all have your units set up as far as location? Do you have the bigger one up front or by the console and for what reasoning?

If you can swing it go for the 8, the soft keys make it much faster and easier to make adjustments, unless the 7 is a touch. Arguments can go both ways for the larger unit on the bow or console. If the LSS is on the stern I'd put the larger unit on the console. If you just purchased the HDS-5 and SS it may qualify for a $300 rebate.

http://www.lowrance.com/en-US/specialoffers/