I posted a question a while back regarding enlarging a window on my main floor (window is in my living room). Now I’m back asking a second question, this regarding enlarging another window in my house. This one is on the second floor (master bedroom) and same as my original question is on the gable end wall of my house, which isn’t bearing any load. Above it is my attic, so only the gable portion sits above the wall as the joists in the attic run parallel. 
Currently, I have two windows in my master bedroom, they measure 65″ high x 32″ wide. A centre wall sits between the two windows that measure 56″ wide. I’m planning to turn the two windows into one large window that will measure, 65″ high x 120″ wide (10 foot span). Since I’ve already torn out the wall, I’ve discovered the spacing above the windows to the top plate measures is 7.5/8″ high. From my research, for a 10′ span window opening the suggested header size is 10″ in height. I’m wondering if that’s definitely the case for a wall that doesn’t have a true load it’s bearing? Would a double header that is 8″ in height be sufficient without the fear of any sag developing over time or is this a case where I should consider using an LVL. for at least 1 of the two header pieces? Appreciate any advice that can be shared. 

Thank you,
Peter