From what I can see, the limiting factors that decide the amount of torque the centre can transfer to the axle are -

1 Area of gear in contact with the block
2 Friction between the gear and block
3 Amount of clamping pressure applied to the block by the action of the cross pin on the ramp.

The area available to transfer torque being so small, means this is the major limiting factor of this type of mechanism. When the load on the gear becomes sufficiently high, oil between the gear and block goes into shear and metal to metal contact occurs.

I wouldnt be using one behind a N/A SR in an H165, but would probably be good behind a hot A15. I would make sure I had a magnetic collector plug in the diff though for wear particles.

I assume the block would be made from nitrided 4140 or similar???