Need more pics. Id love to see different angles. Plus everyone's tastes vary. I like the idea and when you find what really speaks to you it will look great! At first glance I think they look a little short. Since they look to be an 1-1/2" apart in the centre, I think my eye is expecting them to be a little closer to the quarter end cap. I'm also thinking to finish the ends, a straight chop for the center and the same angled curve as the rear quarters on the outer ends would be a stronger look than the slant look. I know it's just a mock up but I would add a little bull nose to soften the look of the top edge so it's not razor sharp. When I was thinking of a similar idea, rather than a split in the middle, I had an 1" step down in the centre. Almost as if you cleared a 20" section to help see our the rear view mirror.
If you have a friend with a metal brake you can use bendable aluminum and then panel bond the ends with Lepage H3300 two part epoxy and end up with an extremely strong and nice looking piece.