Quad motor tailsitter

I’ve been working on a dual motor tailsitter for a couple of years. I’ll never been able to produce stable flight. I’ve been able to hover, go to FBWA but never got stable transition back to vertical flight and landing. I was thinking about converting my plane to 4 motors by adding two arms to it where the dual motors are today and placing the motors on the ends of the arm thereby having 4 motors. My question is this. Can the quad motor arrangement be a rectangle instead of a square? The spacing for my dual motors is over a foot today and don’t want have the new motors be that far away from the body. Thanks.