on the tip of the strut rod there's an area where you can grip to tighten the nut with an open ended wrench/socket. How do I torque it with a normal torque wrench without spinning the rod and nut together?

 

you mean the middle strut nut.... i just tightened mine nice and firm with a allen wrench.
its a nice size steel shaft and so far i havent stripped one yet.

but the cheap struts that came on my ground controls coilovers i bought used they were so cheap as hell and no way to hold the strut..... i had to use some vis grips on the shaft between the spring. definatly not good for the strut shaft im sure!

 

yes middle strut nut, attaches to strut shaft

kyb's use a regular nut and at the very top is a little section that you can hold down/use pliers to grip so you can tighten it. And I do not want to have to grip the shock shaft to torque it down properly.

 

You could put a torque wrench on the top part and a regular wrench on the center nut. With the strut out of the car, action is equal to reaction. So the torque you measure is the torque of the nut.