At first, I only played with a pick. Later, I'd play fast stuff with it, then slow stuff with fingers. Now I mostly play fingers, and drag out the pick when the notion strikes me.
I use the big Fender triangles, #355 Heavy.
If I were to recommend any kind of practice routine, I'd just suggest do what you usually work on with the pick, instead of your fingers.
Over the years, I'd originally set a two-channel amp, one for pick tone, the other for finger-style. As it's gone on, I've gravitated to a one-sound-fits-all, and adjust where I'm playing to achieve the just-right part.
In the old days, I'd pound, and often broke strings (strangely enough, E's and A's). Then I discovered the gain knob. . . . .
I often will adjust the action a bit higher to compensate for the pick, it just makes a bigger wiggle, and if I set it real low for finger-style, it will begin to rattle with a pick.
That sound is always in the back of my head. Bob Taylor talks about the 'bone tone': How fleshy or bony your fingers are will affect your tone. I could never get a sufficiently snarky attack with fingers only, so that was that. I think it's a much firmer tone which I prefer.
IIRC, Anthony Jackson strictly uses a pick.
Joey