The Develop System works by how much YEN you pay into it, there are specific items that can be obtained via each cost amount.  You can reduce the time of development depending on how many "Builder" type Digimon you have in the specific farm; and increase the quality of items by having multiple of the Farm Good "Developer-Know-How".  The develop result is not locked in until you recieve the DigiLine message; ergo, allowing for a save right before the time runs out and if you do not like the developed item, reset the game and try again.