Were using Hitecs Micro 05S in most of our foamies, small footprint, end-block connectoins, lightwieght, channel 1-4 and 6 and its auto shift ability allows any TX to operate it.
The HFS-04MG and the Electron 6 are also viable considerations with some small weight penalties.
http://hitecrcd.com/Receivers/HFS05Ms.htm