The antithesis of the Idler is a DD in my view. My experiences of ownership of each and having compared them is the DD is fleet-footed animal, there is not a trudge in the mud to be found.
The Idler is a heavy-footed beast, there is a lot of taming required and mass does seem the most successful at reigning it in, and that is not going to get it out of the starting blocks with any verve.
A mass set up on a Wall Shelf will not allow for much peace of mind. A DD TT on a Wall Shelf has proven to be quite a valuable mounting method when experienced.
