If I had the money I would opt for an 8 on the dash and a 7 on the front. The 8 will still have the hot keys like the ten for quick changes from screen to screen and would be plenty big. Then use the money saved from that to get the LSS1 and a 7 for up front. The LSS1 can be used to run DSI and side scan for both units. Check out BBG marine for some great deals on combos like a 8 and 7 with LSS1 for one money with everything to have them connected. They also have other combos like a 5 and 5 or 10 and 8 or 7 and 7. Lots of options but I feel the 10 is over kill for the extra money. An 8 and 7 would be my choice for sure. Good luck with the purchace. What you doing with your big screen LCX 113 HD C?