This is really two topics in one post, so here goes...

I'm starting to learn tapping and running into some painful difficulties. When trying to tap the 19-15-12 Em arpeggio, I'm seriously hurting my pick hand finger by jamming it super hard into the 19th fret to get a good sound out of the string, but all I keep getting are whimpy sounds (unless I really smash my finger into the string producing lots of pain (which is not fun). I have a Parker NiteFly Mojo guitar and using line6's insane setting (which should be good for things like tapping since it's got lots of gain, etc.). I am wondering whether (i) I should take the pain and build up and good callus on my pick-hand finger, continuing to smash it super hard into the string to get any sound at all, or (ii) it's an issue of setting the action higher to get more distance between the string and the fret, or (iii) something else entirely? Any more experienced players want to offer some tips / advice on this?

Thanks!

You actually don't need to "smash" your finger on the string. You must do it the proper way. Try loosening up you right had a little, and definitely wait for a hardening of the tip of the finger in order to avoid any serious injuries.

I just began tapping a few days ago after checking Kris 1on1 lessons here at GMC, and it's definitely not about "smashing" the strings, instead you should just hit the string and do something like a "pinch" when releasing it.

Just check Kris 1on1 videos, tapping lesson nº1, watch how he moves the finger before releasing the string each time he taps it, I bet that will help

don't rush the tapped note like it sounds like you're doing, do it ultra slow to ensure each note rings out the proper amount of time. Sometimes if you tap it then kind of pluck it as you pull away to ring out the next one, it sounds better. You might turn on compression, if you haven't. A lot of time, I'll tap with the side of the pick to really accentuate the tapped note. Might try that as well.

Your sound,strings action etc is pretty related to sound of tapping,that's for sure.
But most important thing is proper technique.
Listen to advices above,it'll help you.

Thanks guys for the tips. Will just take it slow and be patient. I'm sure I'll get it sooner than I think.

It really does not matter if you come to the string hard from far above the fretboard , more important is to keep the pressure when you press the string and that way let the note come out..you don't need to hit it very hard but that after fretting pressure keeping I find important (not hard one though but constant so it can hold the tone)...Ofcourse you get bad blister when you try this technique for the first time so you should take it slowly until your calluses build up..