I know this is super late, but if anyone else was struggling, I jotted down the good Roy ending below:
Slight spoilers, but it's just a listing of the required responses without any additional story context.
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- "How can I help you sir?" (+1)
- "It'd be helpful for my work." -> "Accuse him of lying." (+1)
- Select the "More" option three times. -> "Accept" (+2)
- "Accept the job regardless." (+1)
- "You can leave and come back later, you know." (+1)
- "Need some bandages?" -> "Good luck." (+2)
- "Do me a favor." (+1)
- Any combination of answers for when Roy is outside doesn't seem to matter and gives nothing, so do whatever.
- "Go right ahead." (+1)
- "Accept his help." (the first set of options where both are the same) -> "Deny his help."
You seem to need 10 points total to trigger this specific ending and will have enough at #9 above. So the last one ("Deny..") is just to get the final scene going.
Also, for the first set of options, you could also answer it as: "Your kind isn't allowed here." then do "How can I help you sir?" for the exact same amount of points (+1 total). Either way works.