You have not had any responses, so I will from the various service manuals i have.
For these fasteners (M8 x 1.25) doing the job they are supposed to do, the torque ranges from 23 to 26 nM with Loctite for security/safety.
M8 x 1.25 in other places have a much lower torque as they are not holding things on tight.
Maybe a simple approach, but I just tighten those "critical" fasteners up quite tight bearing in mind the material they are going into and not wishing to strip threads.