I 'd recommend that you atleast give 5-8 hours for the jam or maybe if your schedule is too busy, you can cut it down to 3-5 hours per day. It also depends upon the game idea and your skills, if your skills are high enough, then its no biggy, and even if your game idea is like big idea then must give atleast 10 hours per day on the jam. If i were you, i'd pause my indie game for the jam cuz i love jams more then my own indie game XD, if you wish to make a game, then good luck :)