Just to update this, I took the boat to the lake this afternoon and reversed them. Made a world of difference for me. The 898 screen just isn't as bright and having it at the console, I was able to see everything just fine. The 899, mounted to the floor of the front deck, was brighter and therefore I was able to read the screen better from a distance even in the bright sunlight. I'm going to start using them that way now. I had really been disappointed with DI and SI on the bow before.
When I initially bought them, someone on here suggested that I mount them this way but didn't explain why and I just felt that I wanted the best one on the back to search for areas. I thought this might help someone in the future.