When I had an LP12 Lingo, it was on a Target wall shelf and my impression was the same as yours: large improvements to the sound (compared with having the TT on my rack or on a table). Two other things I did which also helped were 1) remove the Trampolin base, 2) place TT plinth on Audio Technica AT605 adjustable isolating feet.
The AT605 foot is no longer made. It gave a firmer support than the Trampolin foot but still not too firm. I would be tempted to try a footer from Herbie's Audio Lab as an alternative, as long as you didn't need a height adjustment feature.
The AT605 foot is no longer made. It gave a firmer support than the Trampolin foot but still not too firm. I would be tempted to try a footer from Herbie's Audio Lab as an alternative, as long as you didn't need a height adjustment feature.