I would like to compare the Sicilian Scheveningen
[FEN ""] 1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 e6
with the Sicilian Najdorf
[FEN ""] 1.e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6
Please note that I am only concerned about positions where the two openings share a common pawn structure; meaning Black has pawns on e6 and d6 and not on the positions in the Najdorf where Black has played an early
...e5. In the lines where these two openings share a common central pawn structure, what are some of the characteristics that differentiate the two openings regarding piece placement and Black's minority attack on the queenside with
b7-b5? I am mostly interested in contrasting different middlegame plans and tactics based on piece placement such as the knight at b8 going to either d7 (typical of Najdorf) or c6 (typical of the Scheveningen) as an example.