The most efficiency you would get of a typical 1/4wl antenna, is when it is perfectly perpendicular to its counterpoise/groundplane.
Having said this, any antenna can be bent to "infinite" (discarding that it may break) thus reducing its efficiency by changing its polar diagram and increasing SWR at the Radio side.
Helix antennas may be good for mobile operation but their efficiency is not as great as a perfect whip. Trade-offs always.
We have been using something called Nitinol Wire with great results in terms of RF and physical. It can be bent, tie knots, and other eccentricity uses and it will always return to its programmed state (ours is rectilinear/straight).