I have only used Jens and he has done an excellent job every time. I used to use amateur handlers provided at site until I realized they did not even know what judge was looking at and for. If you are serious, don't count on luck that the judge MIGHT see best qualities of your horse. Amateur can also bring out the most of your horse's lesser qualities.
You might try Klaus Schengber of HIGH POINT HANOVERIANS in Maryland. He generally does this show and is usually happy to pick up handling jobs. You could go to "highpointhanoverians.com" for his contact information. He handled for me last year at that show, at the last minute, and did a wonderful job with an inexperienced youngster.
Yes, I think most breeders/owners use professional handlers for most of the competitive in-hand shows, both DSHB and hunter breeding. I have a fused ankle from an eventing fall so limp a little, and am afraid that if I am "off" my horse might look off to a judge since it all moves pretty quickly in the ring~