Shopify Product Imports - Complex Spreadsheets

Looking for a freelancer with experience in complex product uploads from spreadsheets into Shopify. Some of these product spreadsheets have lots of variants/configurations and other spreadsheets just have a lot of sku's but no variants. I run a digital services company and this freelancer will help me provide services to my end customer. Freelancer must be able to start ASAP and speak English fluently. I am hoping to find someone I can continue to partner with and outsource work to.