With me it's lid completely off as well.
With the lid on and up, I can get drumming through the speaker by tapping the lid so it's clear it acts as a big ear lobe for airborne energy. With the lid off together with the Isonoe feet and solid shelf mean I get virtually no feedback at all, however loud I play or tap the plinth.
One thing that puzzles me though is why removing the lid seems such a problem to some. I bought my 1210 new in 2010 and unless earlier models were different, removing the lid is simply a matter of opening to the normal detent and lifting it straight up. The hinge tongue draws straight up and clear from the slot in the hinge body on the plinth. Seconds to take off and set to one side and seconds to replace. Seems like great design to me as the lid is well located and can't be readily displaced when the TT is not in use.