Matt,
No "sapping" so far. Here is a pic of the other hitching rail we put in by the round pen. Don't pay any attention to the good lookin bald dude, or the hot chick... the rail is behind us. They are 42" in the ground and about 42" out of the ground. The top rail is attached with 10" lag bolts, then on top of the lag bolts I used some 2" flat bar and made a strap that is lag bolted in.