I think it probably does look better having the board like it is than it would rotated, so it's like "wide-screen" (and our field of vision is wider than it is tall). But I just kinda thought of rotating it as a knee-jerk reaction like "omg the air-flow isn't going the right way!", but it doesn't matter since you're getting nice temps anyways.
As for the mesh, I agree that something needs done about the edges. Personally, I would have cut circular holes instead of squares, and try to get the edges of the mesh to go inside the edges of the cut. Basically, on the inside of the desk, groove around the edge of the cut just enough to have the mesh fit into the grooves and be close to the outside of the desk. Then round the "lip" that the mesh will be pressed against towards the inside so that it will appear more flush with the mesh.
This way, it would look much cleaner and allow plenty of space for filters between the fan and mesh. You don't want something as nice-looking as that getting all dusty now do you? Plus the filters should help dim/diffuse the light and make it softer.
I realize that you can't really make the holes circular now and the fans will look odd if they're not almost flush with the outside, but you can still try what I suggested with making the groove for the mesh to fit into.
Sorry if any of that is difficult to understand, I'm having trouble thinking how to explain my ideas
Good work nonetheless, it's very nice-looking