If my opponent mulligans several times during setup, may I choose to take 1 card from the top of my deck, look at it, and then decide whether to continue drawing my next mulligan?
When drawing cards for mulligans you must announce how many cards you are going to draw, up to the maximum allowed. If you don't announce a number ahead of time, then you must draw the maximum amount. You don't get to look and decide as each card is drawn.
Source: TPCi Rules Team (2015-11-19)