Those of us who've played real-life tournaments do have substantial chunks of opening theory memorized--first moves for sure, plus most of the replies (and sometimes even more deeply than that).  This includes the proper cube action in some cases.  This opening theory is also "tuned" to the current match score, and in some cases even to one's knowledge of an opponent's playing style.

For purposes of learning, I'd suggest trying to think things through yourself and making your move--then consulting references immediately afterward, while the position and roll is still fresh in your mind.

I hope folks like alanback and playBunny weight in on this subject; they know a lot more than I do.