If the distance is known, or you're really good at estimation and the yardages are under 40 then the lighter/faster arrow isn't going to gain you anything over the slower, theoretically more stable arrow. Faster arrows really only come into play when yardages are mis-estimated. You should see the lob my spot bow (~200 fps) throws at 80 yard targets, it looks like the arrow is going 8 feet above the bail before it drops back in but the fact that I know it's 80 and not 80.5 lets me set the scope and know they're going to be in the white when I get down there. If I had to guess the range, they might not even be on the bail but my 320 fps 3D bow with only about 3' (estimate) of arc definitely would be.

In short, if it was unknown yardage, I'd go with the lighter arrows.