Customize my Shopify Store

Hello and thank you for looking. I would like to have a few questions answered to be sure you and I are both clear on what I am looking for. Overall details: Someone goes to my website and can fill a box to 100% capacity of clothes for x amount of money. So, what I am looking to do is give each category of clothes (dresses, pants etc) a percentage value instead of a dollar amount. Once they reach 100% they would pay for the box. Example: For example, I select a dress, it fills 25% of the box.. then I look through some shirts and choose 3 that fill 40% more of the box etc. Once I fill it to 100% I check out for the flat rate of $XX. Amazon Pantry has a similar function but that isn't 'fill a box for a flat rate' you pay per item. I have looked at some standard bundling plugins but nothing is coming close to my specific needs. Thanks so much for your consideration. SPECIFIC REQUIREMENTS: 1. Assign each clothing category with a percentage value instead of a monetary value. I will provide the list of category and percentage values. 2. Create a custom sorting field on the left side of the page so that customers may filter by percentage value. 3. Can you create a stationary bar at the top of each page that shows a customer how much of their ‘box’ is full? I would be looking for a numerical percentage and a visual bar that fills with color as people fill the box. 4. Set the cart to automatically charge $60 when the box reaches 100% capacity. 5. When the box is full to capacity, automatically redirect the shopper to their shopping cart. 6. Can you add an in-cart upsell popup that allows for customers to add an additional 20% of space to their box for $10. Thank you so much, I just want to be clear on what I expect from the project and for you to confirm your bid.