Looks good, nice writeup and pictures too. I know its a bit subjective but how is the wind noise with cross bars only and bars + rack?
Like you said, it is subjective. When I first put the cross bars on, we drove around for a few days before adding the cargo rack. During those few days we (my wife and I) noticed very little to no wind noise and no whistling even while on the interstate going 70 mph. Zero to mild cross winds those days.
After I added the cargo rack, we drove around with it empty for a day before leaving on a road trip. Once again mild cross winds and a light tailwind. Oddly enough experienced slightly less wind noise ( quieter) than just the cross bars alone. Sounded like air moving over the aluminum alloy platform but higher up from the roof. I think it was amplified some merely because the rack was empty allowing it to resonate.
With the rack fully loaded with luggage, etc. with most of it inside of a roof top weatherproof cargo bag, it definitely created more air turbulence and noise but surprisingly not much more. I think some may have been from the cargo bag and straps moving around in the wind and air. Heavy cross winds and head winds most of the trip.
After returning home from the road trip, I removed the cargo rack and we drove around with just the cross bars for a week before I removed them. During that time we both noticed much more wind noise and whistling. Wide variety of cross winds, head winds, and tailwind experienced during the week. Obviously when experiencing tailwinds the noise was lessened. I thought about wrapping a bungee or rope around them to help quiet it down but decided it was best to just remove them until I needed them again.