Custom T-Shirt E-commerce Setup

I'm looking for an experienced freelancer to set up an online store for selling custom T-shirts. The T-shirts will be printed using heat transfer methods, and I want to provide customers with the option to upload their own designs.

Key Requirements:
- Build an intuitive and user-friendly e-commerce website
- Integrate a secure payment gateway
- Implement a design upload feature for customers
- Ensure mobile responsiveness and SEO optimization

Ideal Skills:
- E-commerce development expertise
- Familiarity with heat transfer printing processes
- Strong UI/UX design skills
- Experience with secure payment integration

Please provide a portfolio of similar projects. Looking forward to your bids!