I can’t answer to you directly, because I never dived into all those details. But I can tell you where you will find the answer:
3GPP 23.122 chapter 4.4.3 PLMN SELECTION
It starts with this :
“The ME shall utilise all the information stored in the SIM related to the PLMN selection; e.g. “HPLMN Selector with Access Technology”, “Operator controlled PLMN Selector with Access Technology”, “User Controlled PLMN Selector with Access Technology”, “Forbidden PLMNs”, “Equivalent HPLMN”, see 3GPP TS 31.102 .”
So I guess you’ll find answers in 31.102 as well.
Have a good read and please let us know your findings.