I am a couple hours south of you if you ever want to swing by, I am about 5 minutes off 95 at the NH/Mass border. Check out You tube, there is one person i have seen, that shows how to create a plexiglass guide to mark center on the antler pieces and to see how the tube will sit. He also shows how to drill the antler on the Lathe.
with any material like bone, antler, etc you are supposed to make sure you use a respirator. Apparently the dust gets into your lungs and does not leave. I have turned some antler and the biggest issue was drilling the hole. the antler is not round so it is tough to hold it. I use vice grips and drill in a series of two holes, the first smaller. Then the second follows the hole and it is easier to hold, at least for me.