I guess I would differentiate the equations to find bestpoints to aim for, rather than feed them into excel for graphs. But now that I see the graphs side by I think your way is better.
Its easier to not get confused with the graphs side by side, rather than pages with equations.

Most importantly, and what would been achieved either way, is that you have demonstrated mathematically is that electric propulsion is realistic for this project, and since OP preferred electric propulsion, I would assume the matter of propulsion is settled.
I do not quite understand your airfoil selection (flat bottom), but you made it work theoretically so why not.