Two airlines, two different ways so far.
One we set the actual MDH if possible. If not then we would set 500 feet.
The other we always set 350 feet no matter what.
Different airlines, different philosophies.
As long as you can get your head wrapped around the reasoning for the SOP and you know that it's safe one way is probably as good as another.
As a side note the known obstruction thing brings back memories of Roanoke. When the wx was at minimums the older aircraft, without RA's would get in while the newer ones didn't. Seems there was a bit of a hill just before DH and it would set off the minimums call about 50 feet too early. If you weren't expecting it you could react and go around a bit before you actually had to.