So I did a foil mod last night. I used some aluminum tape I had for HVAC ducts. I first tried it just wrapping the cable in the tape followed by blue painters tape to insulate it. I took it outside in my driveway where I have limited view of the sky and it made no discernible difference. So I brought it back in and opened it up again, and removed what I had done. I then laid the cable across the factory shield and covered the factory shield and cable with the foil tape followed by a layer of painters tape for insulation. I did not extend the mod shield past the edges of the factory shield. So a short section of the cable, probably a half inch of cable plus the connector is free. I took it outside in the driveway again, and again could not detect any difference. So I took it out in a large open field where I often fly and it made no difference that I could tell.
Now I did not have any trouble getting sats before this so that is probably why I could not tell any difference. At this time for me, this mod appears to do nothing.