Fritz, you seem like an honorable and decent human being. It is unfortunate that the events unfolded as they did, but in that situation I believe that there was little that could have been done to change the outcome. As others have stated in this post, I would welcome the opportunity and be honored to hunt with you. Mistakes happen, it's what we do with those mistakes that makes us into the people that we are. From what I can tell this has made you pause and reflect and to learn some valuable lessons that can be used down the road which is only a positive. The one suggestion that I would have is that if you wanted your client to shoot out to 40 yards than have him do it. If that is a problem with not only this client but others as well maybe add a stipulation into the contract stating clients will perform a proficiency test out to 40 yards with the consequences being if they do not pass then they can not hunt elephant with a bow (rifle only). Also have them shoot other game with the bow to get an assessment of skills and abilities before doing the elephant. As others have stated though being proficient on a target is one thing, being proficient when within several feet of a behemoth is a whole different thing. If they can't be proficient at a target though there is little chance that will change when within striking distance of an elephant.