FWIW, I use Ultralink locking bananas, which fit perfectly into the 4BSST(C) and 6BSST(C); not cheap, but very well built. The speaker cable twists into the plugs for a secure compression fit; no soldering required. I use them in a biwired system, with 12 gauge/4 conductor Ultralink CL3 (inwall) cable for LF, with the conductors doubled up (that is, twisting two conductors into one strand), as my cable runs are long and I want plenty of copper along the path. For mids and highs, I do the same thing with 14 gauge/4 conductor cable.
You can, in addition, use their industrial-weight spade lugs on the amp terminals if you wish to biwire. I don't see these listed on their site, but I did order them in May 2013 directly from Ultralink in Markham, ON; Lily Luo was very helpful: 905-479-2831.
http://ultralinkaccess.com/Locking-Banana-Plug_p_96.htmlHere's a dealer that lists the spades, so you can at least see a photo. The speaker cable twists into the connectors for a secure fit. These worked fine with 12 and 14 gauge cable. They are quite thick and have quite a wide span to accommodate thick posts.
http://www.audiophileanswers.com/UltraLink_Pro_Spade_4_connectors_spade_connectors_p/390003799808.htmHope this is useful,
Rich
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Whiney Napa Valley