I have shot deer with both. I have always gotten better penetration with a smaller head. 75 grains and less. Shot a complete pass through last week with a 550 grain cane arrow. the point was 75 grains. I have shot some deer with larger points and not gotten out both sides, the smaller points have always gotten full penetration for me. I choose less resistance over increased weight. I also like hunting with hardwoods where i can get 600-700 gr arrows with out a point, then I can use a little 40 gainer on it if i want and that gets great penetration should I hit extra bone. some folks will argue that their huge points are the best... all i can say is, I have killed 5 deer and a hog with stone in the last 3 seasons. so six big game kills with stone.
4 smaller points- all equaled pass through's
2 larger points- neither got out the other side
so for me i choose a smaller point, really sharp on a heavy arrow
and +1 on what Pat said.