Interesting. I am normally a big proponent of 4x1 and almost against purely vestigial button in principle, But because the cut and your torso length, both look good and I am having difficulty in finding a preference. If you will wear it primarily for business, I would go 4x1. If mostly casual as sportswear or travelwear, then 6x1. That is a really well done suit and very good look for you.