If your bow is properly tuned, your fixed broad heads will hit the same spot as your mechanicals and field points.
If your bow is not properly tuned, then mechanicals will hit closer to or in the same spot as your field points.
Different bows have different IBO speeds. And the IBO speed for your bow should be in the papers from the maker.
The poundage and length of your draw then decides how much energy you transfer to the arrow.
Then it depends on how heavy that arrow is.
All this decides how much speed, kinetic energy and momentum the arrow will have when it leaves your bow.
Archery Calculators-Calculate Arrow Speed, Kinectic Energy,Front of Center %
This is not totally accurate, but gives you a good indication of the speed you will get.
Calculators – Archery Report: news views and reviews
This tells you what Kinetic Energy and momentum you get.
mudslinger, I stand corrected
The Rage has a 2" cutting diameter and the GrizzTrick2 has a 1 1/4"x2 cutting diameter.
I am not sure what is best of 2"x1 or 1 1/4"x2, but I know I prefer a fixed broad head on bigger animals as I said earlier
I have 89.973 Kinetic Energy and 0.6921 Momentum, so it should be plenty for using Rage on Kudu, Wildebeest and similar sized animals.
But I am a person that always plan for worst case scenarios, so I expect to hit bones. Specially because I prefer to put the arrow very close to the shoulder.
I also prefer to have a exit hole for increased chance to get blood on the ground for tracking.
So I use a strong all steel fixed broad head with 1 1/8"x2 cutting diameter.
If I had been shooting a bow with less than 60 lbs DW, I would either use a similar head with 1"x2 cutting diameter or a Silver Flame from German Kinetics.
PS. I really think that the new Rage with the chisel tip looks very promising, but I wish they could make it all steel and use a bit ticker and stronger blades.
Another mechanical with a large cut that I think looks promising is the NAP Killzone.
If you want a really big hole, you can always use the new Slayer Trauma 3 Blade Broadhead 150gr, but you better have the bow for it