[KurtSF]

To do it right, use a RoR calculator and input your acceptable risk of ruin based on your winrate and standard deviation, and drop down when its exceeded.

Note that your example doesn't take into account the variance in these games. Depending on buy in limits and game character, live games can have both unusually high and unusually low variance, so this cannot be "answered" based on the information you have given.

But as a SWAG, I would drop down after losing a few buyins, both to build back up and to get your confidence back to play in the bigger game. Say at $3200.

The stupid question is not asking.