Best way to join 45 degree window screen stock corners?

[Dennis S]

I only have to make 2. The originals are shot. I'll tell the owner that butt joints were recommended. The current ones are 45 degrees, so that's what I was going by. I am just going to use screen tacks and cover the edges with screen molding.

If I use butt joints, should I run the top and bottom stalks out to the edge or the vertical stalks to the edge?