If you're shooting north or south, and you shoot all day long, if you're a consistent shot, then you may find your groups moving toward the sun. (left or right). But unless you shoot all day long, you probably won't notice. Adjusting sights for this is not the norm. Shooting into or away from the sun, As if there was some magnetic pull on the lead and copper to adjust the projectile tragectory toward the sun, (not the case), is to shoot normally. -How the sights are set for not shooting into or away from the sun. As for morning or evening sight settings in low or limited light conditions, as long as you can see the target, and see your sights, then again, there's no change required. If you can't see them, it's time for glasses, some sort of glow sights, Or just possibly time to quite shooting.
Wind drift calculations can be found in in any reloading manual. The factor depends upon the bullet weight, velocity, caliber and design. I have some old Speer reloading manuals available for the price of postage if this is what you need. Reading a reloading/balistics manual will most likely answer many of your questions.
Rate of twist will not make up for the trajectory or wind drift. Rate of twist will inherantly affect overal accuracy of any particular caliber. Compare the lower twist rate of the 32Win Special in an early Win94 against the 30/30 in a Marlin or Winchester94. The Marlin is most often more accurate. With the 32Win the least accurate. The bullet isn't spinning as fast.
I'm surprised that you didn't ask about shooting up or down hill. The affects of gravity on a long shot. Again, information that can be found in most reloading manuals.
-Steve