I note that Magnus broadheads are Teflon coated, which is advertised to increase penetration. Don't know if any tests have been done to validate this.
I'm 69, in the same boat as you are, weight-wise. Also have shot a lot of 3D, and have used the stuff that makes it easier to pull arrows out of 3D targets, at times, but don't know if it would increase penetration on live animals. Would be nice if there were some tests, like Ashby did, as sometimes these things don't work out like we would imagine.