I don't know what your KE would be downrange, there are several different programs that will calculate that for you fairly accurately. In my own humble opinion, any modern compound, which you have, will kill a deer just fine if you hit him. Your arrow weight with a good, quality broadhead will be incredibly effective, if you hit the boiler room. Your penetration will be measured in inches of dirt on the other side. My arrows are currently about 440 grain (which I consider on the light side). I am currently pulling about 65#'s. I thought about going heavier, but maybe next year, as I have spent enough money this year already (new bow). I do have to be careful with yardage, but I know my limits. I use a Magnus Stinger 125 and I can't wait to get after elk and muley's in 5 weeks. I am not worried about the energy, just the accuracy at the moment of truth. I know if I do my job, my equipment will do its job. Get comfortable with what you shoot and get after 'em!!

JMAC

PS As an engineer as well, I do find myself going WAY overboard with my equipment, to the point that I sometimes think more than shoot. I have since seen the light..