PEPs and protons

What are preferred docking points on the nucleus for PEPs and protons?

The basic structure to answer this question is there, but there still some details to iron out.

What is the logic behind the order of the positioning of PEPs?

There are sometimes several options for a PEP to attach itself to a nucleus. Is there a logic to the order in which it happens?

How easy is a PEP connected to a nucleus able to connect to a proton and what mechanism is responsible for this?

This of course is related to a transmutation step.

Does the direction of impacting particles (PEPs/protons) influence the chance to hit the right spot?

This might determine the order of attachment as well as the likelihood it happens.