Custom Shopify Recurring Donation App -- 2

I'm seeking a talented Shopify app developer to create a custom donation app for my Shopify store. The app should primarily support recurring donations.

This app will be like the other Donation apps, but with some Key Features:
- The app should allow customers to set up and manage recurring donations or a single one time gift.
- Be able to set custom presets ($10, $20, $50,...) or "Other" that opens a form field they can input their custom amount
- Custom amounts are not multiples of $1, but rather, if a person enter $250, there is one donation for $250.
- A custom widget that allows the user add the widget to Pages, Cart, or Products
- Custom code that can embed this widget anywhere
- Full control over what shows and where and how (e.g. title, description, buttons, etc.)
- After donation, allow for redirect to Cart or just a simple popup message
...

Ideal skills for this project include:
- Extensive experience with Shopify app development.
- Prior experience in developing donation or fundraising apps would be a significant plus.

Please provide examples of relevant projects you've worked on in your proposal.