We have an Ironman steel roofrack with a mesh floor and side awning on our LC200, that does create some wind noise, but the amount of noise seems to vary depending on various factors, e.g, what's on the rack, maybe wind direction. Ironman don't make a wind deflector so can't comment on if one would help. After a while driving we don't really notice the noise as much anyway, and our music is often being played quite loud!
We remove the roof rack when not needed! I'm the main driver of the car and don't necessarily like it being on between trips. Saying that, we don't camp every second weekend - if we did, I guess it would stay on!
We have our rack hanging by chain off the roof of the shed, attached to a (boat)? hand winch and pulley system. When needed, line the car up underneath, place a couple of foam pool noodles on the roof (just in case) and slowly lower the rack, do up the bolts, pull out the noodles...done by one person in a matter of minutes. Reverse procedure when removing.
Works for us, but as I said, we prefer not to leave it on for normal driving, I wonder if you left it on all the time you would just get used to the noise and not notice it at all! We did a three week road trip and it certainly seemed louder at the start than at the end!