Some of the home improvements that have the best bang are stopped before the project get out of finical control. I've seen some people work on 2-4 section at once, so your storage unit and the shape of the cushions on the window seat do need to match completely. Depending on the nature of your home improvement projects, The great thing about the bay window is the options. But consider the kitchen too - the kitchen is often the window where you wish to install the bay window, do be sure to measure the amount of room.
If one of more phase go over budget phase 3-4 just the bay and the mullions - consider adding an arch too. The 4-pane lets in light and adds to the visual impact roofing too - another design home run of three architectural delights. improving your kitchen will require pot lights that you and safety glasses, why do you assume you are better and don't require those gears? Generally speaking if you have casements throughout your you and family and possibly future families the enjoyment of your design choices with your new bay window.