From the looks of it I wouldn't let KE concern me at all, unless you're going after elephants. Of the three I would pick one of the 340 shafts, get broadheads on them and see which groups the best. Let the bow/arrows tell you which is the better of the two. Considering the bow weight and arrow length I just wouldn't try a 400 spine. I think the 340's will work better with broadheads. Depending on how long your shots might be I'd lean more toward the Excels. The choice is ulimately yours.