In general the MAX5974 dead time does not have a specific value and it should could cover the maximum turn-on time of the power MOSFET. Considering a typical maximum switching frequency of 264kHz, this implies a 3.8us period and a 1.9us pulse assuming 50% duty cycle.
Thus the Dead Time selected must be significantly smaller than 1.9us. Looking at page 19 of the MAX5974 IC data sheet, Dead Time section, it details how to select the Dead Time resistor that can provide a range of 40ns(typ) to 400ns(typ) dead time. The 40ns delay time is much smaller than the 1.9us pulse, however we also need to consider the MAX5974 IC's NDRV and AUXDRV Rise and Fall times. On page 4, Electrical Characteristics table, NDRV Driver section, Fall Time and Rise TIme rows provide times of 14ns(typ) and 27ns(typ) respectively. On page 5, Electrical Characteristics table, AUXDRV Driver section, Fall Time and Rise TIme rows provide times of 24ns(typ) and 45ns(typ) respectively. Thus for the NDRV when considering Driver Rise and Fall times, this implies an 81ns worst case pulse for a 40ns Dead Time pulse (27ns + 40ns + 14ns ). This pulse is still 23 times small than the 1.9us switching pulse and should be fine. For the AUXDRV when considering Driver Rise and Fall times, this implies a 99ns worst case pulse for a 40ns Dead Time pulse (45ns + 40ns + 24ns ). This pulse is still 19 times smaller than the 1.9us switching pulse and should be fine. Additionally see page 19, Figure 5 for the NDRV and AUXDRV and Dead Time pulse overlapping details.