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There is no shading and the panels can be north, east, south or west.
Let's make it facing West.
The latitude for Washington DC is 39 degrees, to get the best sun angle for winter operation multiply 39 by 0.9 then add 30 degrees... thats 35 + 30 or 65 degrees from horizontal.
If you want to optimize for year round use, adjustable pitch mounting frames are better. CLICK HERE FOR AN ARTICLE ON THAT.
We can go from there until your question is fully answered as long as you rate my answer so far *positively... I will hold your question open.