Here are two setups I have used over the years, admittedly using compound bows:
Using Easton XX78 SS 2314 aluminum shafts:
Total Arrow Weight = 490 grains
Draw Weight = 65 lbs
Draw Length = 30"
Chronograph Speed = 247 fps
Using Gold Tip 5575 XT Hunter Carbon Shafts
Total Arrow Weight = 375 grains
Draw Weight = 70 lbs
Draw Length = 30"
Chronograph Speed = 283 fps
When you work it out
both setups were in the +/- 66 ft/lb range. More than enough for a Whitetail.
As for fixed v mechanical, the debate continues and will for all eternity. Each to his own. and I am talking compound not recurve bows. I use mechanical. It boils down to personal preference and how they fly and how the shooter perceives they fly (ie confidence). It's just plain ignorant to state one is better than the other. Try both and see which you believe gives you an edge whilst hunting. Touch wood, I have never had a mechanical fail to open.
I have tried several makes/models of fixed and mechanical and I like the Rocket Steelhead mechanicals. Using these, some have been pass throughs, some not but I put deer in the freezer and that there is the name of the hunting game folks. Strangely enough I have had pass throughs and not with fixed also. I think I see a pattern developing here. I have no scientific tests to support my use of mechanicals, just that I perceive I have the edge using these for my setup and my confidence and last but not the least
for getting an ethical kill.
A point to note here is I shoot compound and probably could not even put an arrow in the same county I was standing in with a recurve.
Just my 2 cents
BTW ... to answer your original question, using all the same arrow weights, yada, yada, yada, an increase in draw weight would increase kinetic energy