Without seeing it, it it's hard to say what answer would be of help to you.
One way or another, with this type of side-mounting, the brackets will show.

You can mount them closer to the window in attempt to decrease the distance
between the window frame and the shade.

Shades up to 45 inch. wide usually use only two supporting brackets -L & R.
Do you then need a middle bracket?

Or, you can then use the angle-iron way (where the brackets mount to the angle iron
and stay covered by the shade. The middle of the shade gets support this way
(if you need it for a shade wider than 45 inches).

Here is the link again:
http://myhomewindowblinds.com/07/18/how-to-install-blinds-and-shades-in-a-wide-span-window/