The "dual intent" permits seeking permanent residence, while seeking permanent residence on a tourist visa is not allowed, under most conditions.
"dual intent" doesn't backdate permanent residency once you're started to seek.
"dual intent" doesn't backdate permanent residency once you're started to seek.
>seeking permanent residence on a tourist visa is not allowed, under most conditions.
In the US, it's allowed under your stated conditions. Immediate relatives of US citizens can generally adjust status to PR from any status (including tourist visa/visa waiver) or no status. Although if your underlying status expires you could be temporarily detained on a discretionary basis.
That said, it's better to pursue a K1 if you plan to get married shortly after arriving. It's very unlikely you will be granted a tourist visa if you tell the truth in the interview that you're engaged to someone in the US with immediate plans to marry.