How does Browning use narrators to explore male pathological murderers in My Last Duchess and Porphyria's Lover?

I have been set this essay to complete and have scribbled down a few notes which I think may help me to cover this question

-both are dramatic monologues, rich insight into the feelings & mind of a psychotic murderer

-Porphryia's Lover seems to suggest (possibly because of his psychotic mind) that he should not be punished for her murder - reference to God not saying a word, however the fact that he has even mentioned God suggests he knows its wrong? Reference to natural imagery - bee's, suggests her death was natural & imminent. Also bees are annoying - releasing bees from her suggests he's doing her a good deed.

-Objectification - Porphyria's Lover describes her as if she's a doll, smiling rosy little head - ties in with Victorian period and objectification of women.

-Objectification in My Last Duchess, painting on wall. Use of pronouns MY

-My Last Duchess made very dramatic, as if he's putting on a show, envoy in seat, painting on wall, hidden by a curtain.

Would anyone like to add any points, or indeed amend mine as I'm sure there are problems with them.

I also struggle with keeping a tight focus on the question so any help there would be very much appreciated.

Thank you