"Very low in the sky" depends on where you are. Here at 41 degrees latitude (New York City), they are about 1/3rd of the way up from the horizon at sunset. If you are in the southern states, they will of course appear higher than that.
The Seattle area is at about 48 degrees.
Plus, of course, viewing conditions are best when it’s dark, and I saw them 2-3 hours after sunset.
Thanks for making me aware of that Web site. As to the position in the southern sky, they will be quite low on the horizon here in central Florida at 6 PM EST, soon to disappear from view (tonight, they will have set by 8:30 PM according to the tool).