create feed file for amazon

we are looking for someone who is very experienced in creating large excel data file. If you have previously worked with amazon feed files and know about product variations and how to create them, then this would be easier for you, and if so, let me know in your bid. you need to create a feed file of about 4,000 products. you have to go through our site and enter data about each product into a feed file, item by item. almost all items would have multiple variations for them, where some aspects of the products change, but others will remain the same. in the end the feed file would have entry for about 20,000-25,000 products with variations. each product data will have around 40-50 columns of data, many of which you have to copy past from our website, and some column you have compute the changes by yourself depending on the variation the product will have. if you are good in macros in excel, then this would be easy for you. for example, for variations, you can easily assign formulas to compute and change product entries. we need someone who is highly skilled in above, and who can do this without mistakes. if you create the feed file and if it has errors in it, we would not except your work. so do not bid if you are not able to create and complete the project as we require. bid only if you can do this work in time and correctly. we need the complete work in 10 days.