Custom Magento Shippping Rules Config

Our magento site: [login to view URL] needs to work with some complex shipping rules. We purchased this extension: [login to view URL] which appears to do what we need, but it is difficult for us to configure the extension properly to get what we need. We are seeking a Magento developer who has proven experience using this premium extension, or another comparable extension. The ideal candidate will be able to quickly set up the following shipping rules: 1. All products in 3 categories (100 total products) have a flat rate $40 shipping cost using UPS 2-day air. 2. Domestic Shipping using USPS Order totals from $0 - $25.00 can ship via USPS for a flat rate of $5.50 Order totals from $25.01 - $50.00 can ship via USPS for a flat rate of $6.50 Order totals from $50.01 - $75.00 can ship via USPS for a flat rate of $7.50 Order totals above $75.00 cannot ship via USPS 3. International Shipping using USPS Product Weights from 0 - 3 lbs. can ship via USPS for a flat rate of $35.00 Product Weights above 3 lbs. can ship via USPS for a flat rate of $45.00 Order totals from $50.01 - $75.00 can ship via USPS for a flat rate of $7.50 Order totals above $75.00 cannot ship via USPS UPS shall remain configured as it is currently. IMPORTANT - This magento store is a live website with a heavy traffic load. We cannot afford to have the shipping module disabled at all. The changes will need to be done carefully and not interrupt our customers store/checkout experience. Thank you, Ron Temple Hiring Manager - [login to view URL]