attaching eye-bolt to roof ridgeline
If I may suggest an alternative since putting a hole in any roof is better avoided.

I have a 10/12 pitched roof and I use an extension ladder with a stand-off stabilizer to reach the peak.



The ladder is laid flat on the roof with the stabilizer pointing skyward. Extend the section and slide upward towards the peak and then flip the ladder so the stabilizer hooks over the peak.

Climb up the rungs which offer both hand and footholds. Once you’re at the peak, tie off your safety line, hoist a plank to lay on the opposite side of the peak and insert through the top rung. Lash it off or use pipe clamps and you’ve reinforced the setup. I have used it to rebuild chimneys, antenna work, placing hundreds of pounds of brick, etc... on it.