I used to have 100" screen between my Summits but than I realized that placing absorption panels on the screen improved acoustics quite well. Currently I have combination of diffusion and absorption right where screen used to be and I use regular motorized screen whenever I watch movies(less acoustical importance)
There are motorized or permanent, acoustically transparent screens, which may be an option for you if you want to install some acoustic materials between your summits.
First experiment on cheap before you invest big $$$