I believe you are over complicating things. Though I do believe those things are true, the margin is fairly wide. Wider than how you express those notions. What is indicated, to me, within those is that extremes are unwanted. For example, I expect that any women I might choose for a wife to be attractive (to me), however, there are ways in which I could lust for her body which would exclude her personhood, who she is. There is a lot of room in there.
And, more, I believe God guides us in these things. The Word, the word, the Holy Spirit, and our conscience, along with the Magisterium and our religious advisers, should be relied upon when we are not sure (they, generally come to the same conclusion, or should). If you know you are doing something that is wrong, find out why and work toward fixing it. However, understand, you can only work toward those things. If you could achieve perfection, Christ would not have needed to make Himself The Sacrifice.
In the end, that means (as I understand it), that we must learn to live humbly. We need to look to God and all he has provided for our guidance, and often, to try and stay on the right track. All with the understanding we are sinful, that seeking wisdom is all we have here and now. Well, that and bowing to the One who died for this cause, seeking and accepting forgiveness, and partaking in the Eucharist to join with Christ here. I won’t say that is easy, but I think it is doable. From then on, hope, faith, and charity (love) will fill in the rest.
Maybe someone else knows more, or can put it more correctly. But that is how I see it.