App suggestions? - Adding branding options to garments for sale

Im looking for a suggestion for how I can simply enable my customers to add choices on branding to items I sell, so they can do everything in once go and not have to email back and forth.

The scenario
Currently I sell tshirts, hoodies and other garments suitable for being screenprinted or embroidered. If a customer visits my site they can purchase all the garments they want, but then I have to communicate with them separately to get art files and invoice them for the embellishments. Is there an app that can facilitate these manual steps being something a customer can do at the same time they purchase?

Current setup

  • Shopify is runs the website and payment capture.
  • I am using the shopify app “Quantity Break & Tiered Price” for volume pricing.
  • stock management, dispatch and reporting is run through Cin7

Requirements
There are some complex requirements which is where it gets tricky. Im looking for something that will make up a bundle or add items to the cart, as well as capture artwork from customers, and communicate it from shopify to my customer service team.

  • embellishments are volume priced, eg more screen printing = lower cost per print.
  • garments across multiple sizes and colours are also volume priced.
  • customers should be able to select from available stock on hand only.
  • minimum order quantities can be enforced.
  • screen printing has a one off screen setup cost on top of the per print cost, which is the same no matter how many prints are being done.
  • customers ideally are able to send files to me at the same point they are paying.
  • customers can specify in writing or with a visual mockup where they want to place their art on the garment.

Does anyone have a similar setup? Or suggestions for a (simple) solution?

Any help would be greatly appreciated