Now I am evan more confused.

Looks like I want to start with the tip weight as the part of my arrow choice. After looking at most of these broadheads it appears their ar alot in the 100 grain arena soI assumed that would be the one to go with(have not bought yet). What happens if I go higher then the 100 grain, what will it do to my arrow and flight. what are the advantages and disadvantages to going to a higher grain tip (maybe something I want to do I imagine the impact harder).

Where I am getting confused is the spine of the arrow. I understand the smaller the number the more stiff the arrow (now i do at least). What is the advantages of the stiffer arrow (say 400 difference then a 340) Looks like with my bow I am on the verge of having the 340 as the perfered choice.
what kind of arrow flight is going to be a more consistant arrow flight?