I went straight on through. If you use a 9/16th bit and go straight, you shouldn't pop out anywhere, it just makes a bigger passage way through the body. I don't know about going from either side, that seems like it would be harder to line it up perfectly. Stright through ensures there is a single column of air the same size all the way through. Just take your time and make sure you are lined up as perfectly as possible when you start to dill and you'll be fine.