"My inverted "L" for 160 meters gained approx 18 DBI when going from 6 radials to 60 radials, 60-75' in length. In my case I would say it made a big difference."
Assuming you had a 1/10th decent 160 antenna to begin with (and not a mobile whip), then you should generate a huge pile of Europeans every time you transmit.
You do understand that on some radios an s-unit can be as little as one or two dBs.
My own long experience with radials/inverted L's tracks the published studies: lots more copper equals no discernible improvement on transmit (<3dB). And CERTAINLY no improvement in my ability to copy weak signals.
Low band contesters/DXers would kill for even 3 dB. If huge radial fields were the answer, then my 1 acre yard would be solid copper.
By the way, did you read what N6LF discovered about using 4 radial? PERHAPS using 6 is also very bad practice?http://www.antennasbyn6lf.com/