A few tips on tuning a Perl.
If you tighten the bonnet (item 7) too much the friction of the faucet lever (5/6) pivot against the two #2 o-rings will make it harder for the faucet to hold a seal. You want the bonnet just tight enough to not let beer dribble up through the handle area while still allowing the faucet handle to move smoothly and easily, with just a modest resistance.
Also, any time you break down the faucet for cleaning, put a film of keg lube on all of the o-rings. It helps avoid pinching o-rings during assembly and does make everything feel smoother. The upper #2 o-ring is easily distorted if you assembly the faucet bone dry, so if not keg lube, at least wet everything down.
Finally, if after cleaning and adjusting the faucet still drips out of the spout, flip the #3 o-ring over so the lever ball seats against the other face. And if that doesn't work, replace that o-ring...
fwiw, I have a half dozen 525SS faucets and they are extremely
well behaved, though I did have to tune-up one of them before it fell in line. They're just a pleasure to use...