15 - 19 psi at idle is good.
Harley has no spec on idle oil pressure. basically, if the light is out, you are good to go.
it is important to note that, Harleys do need the same kind of oil pressure as your car.
the main engine components are on roller bearings and the bushings are "drip feed".
you can tell if your oiling system is operating correctly by looking into the tank with the engine running.
if you see signs the oil is moving, you are good.
if you see stagnant oil.....you've got problems.
it's not possible for me to ell you after you ride (X) number of miles the drips will stop.
it should stop or be barely noticeable after around 30-50 miles of continuous riding.
a little drip here and there is not uncommon.
you shouldn't worry about unless you can't maintain oil tank inventory or the bike leaves a puddle every time you park it.
you should also be aware the "sumping" issue will never go away.
it will happen ever time you park the bike for more than a few weeks at a time.
there is a home remedy you can try, but it seldom works and requires removing the oil pump from the engine.
let me know if you want instructions.
the two best solutions are A) don't let the bike set for more than a week without riding continuously until oil temp reaches about 200F, and B) replace the oil pump. (S&S would be my suggestion)
let me know if you need more help.