That depends Terminator, everyone is different. I dont think switching the order of the muscle groups hurt your success, BUT I will say this, if switching the order of the muscle groups affects one or those muscle groups in a negative way(ex. You do less on those ones because you're tired) then don't switch them. Personally I would say do the ones you feel are harder for you first. Now, about the time issue, my full-body workout routine takes from 2-3 hours a day(depending on the level). I usually cut down rest time so that I can finish quicker. So don't worry if you take 3 hours to do it, you're fine. But if that's a problem I suggest doing splits then, like me. Good luck Bro!👍🏼👌🏼💪🏼