Based on my own experience:
I used 4-5NM for the stem crews (clamping the handlebar), 4-5NM for the spacer towers, extension to baseplate just untill fixed (probaly also around 4NM but don't know for sure).
The clamping of the massive alloy stem onto the steerer tube needed around 8NM of torque to grip the steerer enough. I am thinking you need the high force to bent the clamping of a solid alloy stem (because the stem still slips onto the steerer otherwise).
I would advise increasing the torque with increments of 1NM just until the bars don't spin anymore 
I agree with the previous post. 5-6nm in general it´s enough with carbon asembly paste. But for the aluminium stem I used 10nm because the steerer tube kept slipping.
Good luck!
