I park it with the wheel wherever it’s pointed, but it’s most often straight ahead. More important to me is the lean angle due the surface it’s on. I want sufficient lean angle that a bypasser couldn’t bump it over, and that wind gust couldn’t blow it over. If lean angle is not sufficient, I reposition the bike. If I were locking the steering, which I rarely do, I guess having the steering pointed either left or right is fine with me, whichever way seems more stable. My dual sport is parked in the garage right now with the steering pointed to the right, and I’m totally cool with that. I’d say in general that it seems more natural to point a dirt or dual sport wheel to the right.
I haven't seriously thought about the geometry of the steering trail when it comes to stability on the side stand. The trail (offset between the steering pivot line and the tire contact patch) would probably affect the lean angle and favor one wheel direction vs the other when leaning left on the sidestand. My gut feel is the turning the steering to the right leans the bike over slightly more, but I could be wrong. Maybe I’ll think that over someday.