2.5 Qts for a wet refill, 3 Qts for a dry refil. Wet is for routine oil changes and dry is for an engine that has been disassembled, cleaned in solvent and dried.
You could do 2 Qts and work your way up to full with the 3rd. Always measure on side stand, only between the marks for a cold, pre-ride check. If below the marks cold do not fill to top arrow, only enough to get between the marks. With a hot engine, you can add up to top arrow (FULL).
If you think you're going to keep the bike a while, get the shop manual (PN: 99481-00). It will pay for itself in no time.
PS, don't get the wrong drain plug, oil is on the left SIDE of sump, tranny plug is on BOTTOM, facing ground.
2000 Lowrider, 79K miles
95" SE Forged pop-ups
S&S 585Gs on Delkron plate
Zippers Stage III CNC heads
45mm Mikuni and Supertrapp(S.E.) 2-1
Lots of other stuff Harley took years to fix