Bob,,,, I made a set myself and even in this heat I have no temp issues. I have noticed a big difference in air passing my face which is the reason why I keep them.

For what it is worth..........
To give you an idea why I care about wind in my face you only need to look at my beard. Pictured here with my daughters a year or so ago (it's a bit longer now)
Without the tunnel fillers the wind would come up from around the bars and push my beard in my face at highway speeds. A bit annoying to say the least !!!! With the tunnel fillers it stays down and no problem.