Control Room Window Size?

I am at the point where my contrator is asking me for a windows size and height. My control room front wall is 14 wide and 8 foot tall. So, I want to say 5X2 and the top deck of my console should be right where the window starts. IS there any thing here I am missing? Should I go with a 3X5 maybe six foot window. 3X6 :oops:

I just made a quick decision and told him (our contrator) an 8'x3' is what I need, starting at just before where the top ledge of the console is, I want to thank everyone for their time and effort and the quick posts. (I know I answered the question myself in mintues) Duh. Anyone have Ideas though on any rules of thumb or windows sizes they may have chose?...?....? Thanks in advance. :D