E-Commerce Site for Custom Manufactured Products

We are a custom manufacturer with a product that we want to move onto online sales channel. You need to be able to create a website using an e-commerce tool that will allow custom-sized products. For example, you'll select the width in 1/8" increments, select the height in 1/8" increments, select some options for the product, etc. That selection creates one line item on the order. Then you can add more line items in the same way. In your proposal please share with me what tools (front and backend) you'll build the website on. In the sample image below the Frame Type, Color, Width (and width fraction), Height (and height fraction), Mesh are all pull-down selections. Cross-bar is auto-populated based on a calculation. Qty is a number box and Identifier is a text box. You can customize that line item, add it to your order, then add more items. You can modify each line item in your cart.

I will share a site outline with short-listed contractors. Basically though there is a main page that includes a header with logo and menus, a main area which lists the steps required to order and includes the order builder shown below, and a footer containing some more menu links and social icons. There will be roughly 9-10 more pages where we'll replace that main area with other content. One of these will be a contact form with captcha.

We will need someone who has a good eye for design. He do have a basic logo but we need someone who can turn our vision into a visually-appealing and functional site.