RE: Arrow weight vs Arrow speed
I shoot ~565 grains at around 265 fps. On one of my spectacular misses last season, I sunk a 1 3/4" Grim Reaper almost 4" into a white oak. For me, I'll take the heavier arrow every time.
The trajectory point GMMAT makes is good too. If you know your distances, you can pick your spot and do just fine. Bows that now advertise 1 pin to 40 yards bug me because it is license to not practice at distance.