in my experience, your submission does not have to be a carbon copy of what you end up making. you can check the boxes to make them trust your artistic ability - then you can make it yours, within reason. the money controls the art outcome, until you're banksy. a lot of great artists are able to stylistically and thematically change their art on a whim, by studying the materials/style and putting conscious effort in. this is not rare. modern art does not require mastery by any means and some of the more successful artists actively avoid perfectionism.