This is a great post to bring out the heavy arrow vs. light arrow guys. Each of us has our own opinion and set of anectdotal stories. That doesn't make any of us right, necessarily. Personally, I have moved to the "heavier arrow" side in recent years for most game because of my experiences over the last 16 years. Also, until someone does a more thorough study of arrow penetration on live and freshly killed game than Dr. Ashby, I am going to take his word on it unless experience says otherwise.
No doubt that shooting critters in the right spot is the most effective way to put them in the freezer, but there are many things that can and will go wrong at times.
This said, if you want to stick with the shaft that already flies well for you and bump the weight up some, try the weight tubes at 3 Rivers. You can get up to 8 grains per pound of weight increase without significantly changing the spine. Best wishes, Brady