Re: Sectional density, ballistic coefficient and wind drift
There is also BC-vs-Velocity to consider depending on your cartridge and use. This, putting aside accuracy, recoil, barrel life, energy, etc.
If you could choose for instance 243AI 55gr@3850fps -vs- 105gr@3000fps, and you only intend to kill varmints out to ~300yds, the faster 55gr might be flatter and straighter for you.
Just opposite for 600yds..
Play around alittle with ballistic software & see.