Well the 665/3 has straight sides (edges) with a lip on the bottom edge and is designed for 6.5x9cm film, I've seen two differing versions but they are the same fit/plate size. Somewhere I have a couple of scans with the Zeiss edges and codings I'll try and find it.

665/7's are 9x12 holders but I'm not sure about the 665/2's they appear to also be 6.5x9 with straight sides but possibly a slightly ndifferent fit.

Ian