I've found that humbuckers are FAR better pickups for tapping, and I agree with everyone else, tap really hard, often with the edge of the pick, as it's hard itself.
Other things I've found helpful are the level and kind of distortion you use, I would say boosting your pre gain levels while cutting the post gain levels can be helpful, I've just found that tapping 'stands out' better against more fuzz like distortion, if you're not sure what i mean, check out the guitar tones on black sabbath's paranoid, that's very fuzzy.
As well, the EQ can affect things too, I find it harder to make tapping sound clean on an EQ where the mids are boosted, instead, try using the 'smile' EQ, sweep the mids out completely and boost the bass and treble
hope this helps!
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