There seem to be a wide range of recommended torque settings for knock on or hex spinners, the very nature of their use with a hammer plus the self tightening effect probably explaining why. All figures are well above 100 ftlbs though, with Lotus recommending 200-220 ftlbs plus a check after 15-20 miles.
The 60 or 70ftlbs you mention is definately in the wrong ball park for a single nut fixing though, as your experience has confirmed.
FWIW I use a long MG style pressed steel tool for my two eared spinners, which fits in my tool tray. A carefully calibrated shove of similar magnitude to fit or release seems to work fine for me.
