First off, 16 hours is not a problem. 70 degrees "might" be. I would have lowered the beer to my pitching temp (you say 55, that works) then aerated and pitched. Second, I would have used 2 packets (or more depending on the gravity). Dry yeast just sometimes has a longer lag. You need not stress over 24-48 hours (though, I do agree that you probably should target a 12-24 hour lag time if at all possible. Other wise you haven't pitched enough yeast.)
The problem with starting a lager off "warm" is that you will be developing unwanted esters - even during the lag. That said, I have heard of award winning brewers who practice this method with success. But I have always found better results with pitching at or near fermentation temp target.