Re: what's better 168 or 180
The best thing of you can afford it is try them all. Let your rifle tell you what is best. Accuracy is always more important than a few points of a BC. If they all have the same accuracy and consistency potential out of your rifle, then choose the one with the highest BC. If not, pick the one your rifle likes the best. A higher BC bullet often drops more than a lower one due to velocity differences yet drifts less due to the higher BC even though it is going a bit slower. Drop is of no concern in a match but windage is.
Long range shooting is a process that ends with a result. Once you start to focus on the result (where the shot goes, how big the group is, what your buck will score, what your match score is, what place you are in...) then you loose the capacity to focus on the process.