Hello Sir/Madame,
I have precisely read your project description and it seems to be interesting but far from be a simple one.
I'm a fullstack developer with a vast and proven experience of more than 20 year with Web, eCommerce, Business, Portal and such kinds of developments also capable of making your iOS app with backend integration from the very scratch and until ready to production. I'm a professional able to give you the best solution you can find
I'm requiring 7 days (60 h) to be sure you'll be fully covered.
I have some doubts about your project, for instance: What does changing the preview exactly means? That and everything else can be discussed, of course, if you give me an opportunity. But I'm pretty sure this could be done within deadlines I have milestoned you or we may modify them adding new ones or remove existing ones. Just let me know!
Kind Regards,
Luilver