Modeling is a true grind...here is a cheat (Still a grind though)
Note: You should already have girls ready to model and have xShop jobs setup. Best to have one model do an x-shoot first. Just to be safe.
This first bunch resets timers:
GData.Time =9; Player.Energy.Value =100
ModelingWork.LastXShopWorkDate -=10
GData.SearchThemes["Job"].LastPhotoJob -=10
Now, open your phone browser and search for a job. There is a command that doesn't this automatic, but I think there was issues using it. I believe it was if you used it before finding the studio, it would not let you enter the studio later.