i am new to trad, so i cant answer on yardage limit etc, but i have hunted extensively with wheeled contraptions and rifles and pistols, and have to say for me personally that no wounded animal is acceptable, period. Yes, when hunting, the possibility of wounding is a part of it and will unfourtunitly occasionally happen, but as an ethical hunter i feel its my responsibility to only take high percentage shots on animals i have no doubts about killing, and if i wound or miss then i know i have to work on it and become proficient at the range or that kind of shot before i will ever take it at an animal again. But these kind of decisions can only be made for ourselves. everyones experiances and comfort level and shooting style and shooting platform, etc etc etc is completely different.
So if it works for you and you feel comfortable with it then you are the only one that can make that determination. For me though, i will be taking only shots i KNOW i will make and stick to my self imposed limits.
Happy Hunting
Fin