My opinion, and we all know about opinions; but having worked with engineers in fluid dynamics in the past, what my learning was that sure these items work in the engineering sense of the fluid dynamics, but pay back or value requires many many miles, i.e trucking companies, whose trailers are always on the road justifies the $200 for a trailer set. I'd suggest that for most of us that only trailer a few times a year, I'm not sure you will get value.
Now, you being on a V nose, or a Triton 167 narrow, compared to my Triton clam shell, which is like a parachute, that I have seen the fuel consumption savings with.
Again, just my opinion, and I accept my opinion could be full of "malarky".
Cheers