I opted to use Lionel 022 switches (O-31) when building my layout because I had a couple dozen of them lying around. Now I wish I had bitten the bullet and bought Gargraves O-42 switches to start with.
Stringlining is much more an issue when using older (Postwar or older) cars that are heavy and have high rolling resistance. It was happening to me with long-ish consists so I started buying MPC rolling stock. Now I pull 40 cars up hills and around curves with no problem.
Good luck!