My 1300 came with an aluminum bar bent to the curve of the top of the dash. It had 3 RAM balls screwed to the bar and the whole assembly was affixed to the dash through the two holes that secure the instrument cluster plastic to the top piece. This resided just inside the windshield along the top edge. In practice this worked fine for two items - the balls were too close to use all 3. I had a gps up there and the phone in an X grip.
Motorcycle Larry - a machinist/ST'er made a cover with a ram ball mounted in the center but angled toward the rider. I made a similar center piece with a powerlet centered over the steering axis. A wire ran up inside the pipe to the powerlet. MCL is long since gone, but his stuff comes up used now and then.
Some aftermarket folks sell a clutch/master cylinder reservoir cover with a ram ball attached. It fits right or left.
Someone posted pictures of a bar that he made that spanned the two handlebar sections. IIRC, he did some fancy machining and this looked great, but was beyond the capabilities of folks who did not have a metal working shop (read machine shop) in their basement and the skill to use those tools. We do have a talented crop of members who have done some amazing things.
My VStrom has a ram ball on the top of a vertical bar, which is drilled to match the brake/clutch lever bolts. It fits atop the inside clamp piece with a couple of spacers and longer bolts.
None is better than any other - its all what you prefer. I liked the bar that came with my bike because the phone and gps were mounted up high so I did not have to look down while riding.