Looks like another speed trap , but I'll bite.
There are countless different arrow combos out there for any given setup. Find something that gives you the best of both worlds and you'll wind up right in the middle of your two choices. It also sounds like you expect a certain arrow combination (weight) to make up for poor shot placement (twig , back too far , etc.) , when you should be concentrating on achieving excellent shot placement and finding an arrow combo that flies great.

<---Doug---<<<