Paul, over-torquing even the high quality (125,000 - 160,000 psi) AN bolts can be as bad as under-torquing. With enough torque, the bolt shank can be stretched to failure. If you don't know how much force with which your main spar bolts were installed, you could - repeat "could" - be set up for a real problem. Over-torquing the spar bolts has an additional problem you probably haven't considered (aside from a catastrophic failure under load i.e. failure in flight) - should an outboard bolt fail while it's being installed, I doubt that getting the broken remainder out of the spar without cutting into the wing-skin is possible. At least on the LNC2's.

Use the published dry-thread torque values for which these fasteners are designed. A good (calibrated) torque wrench is a small but invaluable investment for an airplane builder if you really intend to commit aviation in it.

Regards,

Dan Schaefer