Which do you prefer?
1. The LXX should be read with reference to the Hebrew, on the grounds that the translators had access to both languages.
2. The LXX should be read only in the context of the target language (Greek).
I've always gone with option #1. When I began teaching the LXX course, I required students to know both Greek and Hebrew. I also insisted that the class be team-taught with one of my Old Testament/Hebrew colleagues. Students were required to translate, say, portions of Jonah or Ruth before coming to class each week, both from the Hebrew and from the Greek
I cannot stress it enough: all serious Bible readers should try to learn Biblical Hebrew if at all possible. I read my Hebrew almost daily. And not only my Hebrew Old Testament. I also read the New Testament in Hebrew, especially when I am in the Gospels.
I love Hebrew. So will you!