Use the torque specs and tighten it within them.
It's amazing to me that we spend amazing amounts of $ on bikes and associated parts only to disregard the instruction sheet and its wisdom. Torque specifications are from the manufatcurer who has spent a lot more $ than any of us making sure it will hold properly.
I have NO idea why anyone would shim and/or grease the threads on perfectly usable parts that were ordered specifically for this setup. Would you suggest I jam a stick in bewteen the brake pads and rim when the pads wear a little?
Sorry, but you need to trust the manufacturer with regard to torque...and USE a torque wrench. They go on sale at Sears every few months and are well worth the $60.
A torque wrench alleviates the gueswork of tightening a bolt. Sometimes it will "feel" too tight but not be even close to what it should be.
Tight is tight and too tight is broken.
PJ