Looks good mate, i made mine using a much stronger standard size futaba servo for pan. After one hard landing the mount snapped off the standard servo drive shaft and catapulted the camera several feet away.
I was lucky, it did scratch the lens but not the area that the sensor uses so it doidnt effect the picture. Tat was on a much thicker stronger spline. But with a servo that small and with such a weak shaft i would be very cautious. One scratch on that lens after its come away and thats on expensive bill