Reading the spec's on those, their rotating the bars 15 degrees TOWARDS the rider.
For the FJR, I never had an issue, BUT, on my FZ6, many owners changed their handle bars
for LESS angle back handle bars (FZ1 bars-straighter). That'd be the opposite of the 15 degrees.
Its my belief, that the most comfortable bar angle would be where your hands naturally fall on the bar
and not making your wrist "twist" say to turn the throttle. The area of contact between your palm and grip
would be best having the most amount of NATURAL contact area... Just my 2cts