I've played many acoustic or nearly acoustic gigs, and I agree that it's important to be able to play the appropriate dynamics acoustically first. When I use a mic, I approach switching to arco the same way I would if I were playing acoustically: no pedals. However, certain pickups really do pick up arco and pizz totally differently. I was playing with my Vic's bridge wing today, and playing pianissimo with the bow comes out of the speaker about as loud as a pizzicato forte.