C# (Xamarin.forms) project for ios/Android/OS X/Windows to handle UI/authentication functions

Hello, We are looking for an experienced C#/Xamarin coder who has done similar work before. We'll provide Xamarin business license if things move forward. This will be a C#/Xamarin forms application that needs to run on a windows desktop/Android/IOS/OS X. The application involves mainly user authentication and login functions. The project is well defined down to the logic level. I will send a detailed, step-by-step block diagram once your bid is under consideration. If you are an experienced C#/Xamarin coder with high rating, good work ethic, eye for detail and sound coding practices please apply. I am not looking for the lowest cost coder I can find. I am willing to pay up for high quality work done right. I will offer bonus over our agreed amount and additional work for job well done. This project pays only when fully finished/tested code is delivered (no milestones will be set/paid for in advance) so do not apply if this is not acceptable to you. Please answer the questions below when you place the bid (bids without answers to questions below will not be considered). Is it understood that this project does not pay till fully tested code is delivered and is not available to work on hourly basis or on mile-stone basis? Do you have experience with xamarin? Are you the developer who will be working on this project if selected or attempt to subcontract? How many months/years of experience you have coding C#? If selected when can you start and how many hours/week can you spend on this project? Thank you for biding and good luck.