BigCommerce Theme Change

I am looking for a freelancer experienced in working with BigCommerce themes to help me change and customize my current theme. I have a specific theme in mind, and I need some minor customization to it. Additionally, I require full setup assistance to get the new theme set up correctly. I am looking for someone dedicated to the task at hand, and who will ensure the highest quality product. With my specific requirements and the freelancer's expertise, we can make sure my goals are accomplished. We already use Cornerstone Lite Custom but need to switch to Cornerstone. The reason is we want to implement a scale for postage which apparently Cornerstone Lite can't do.