Has anyone implemented Element Eligibility with over 300+ element eligible combinations?

Summary: We are looking to implement a differential that will pay 10% on all eligible hours for a small subset of our staff that we are identifying by being in certain departments and jobcodes. Currently we are at between 350 and 400 distinct combinations of jobcodes and departments. This will also include retro so we are looking at setting up 400 * 5 (2000) eligibilities . I am looking at doing this via HDL, but am wondering if anyone has done anything similar and can warn us of any pitfalls or give us any recommendations on how best to create / maintain this. Does it significantly impact performance?

Content (required):We have a resource pool that floats to different units depending on where they are needed. We are looking to pay them a 10% differential on all hours. We are identifying them as being in certain departments and jobcodes. Currently we are at between 350 and 400 distinct combinations of jobcodes and departments. This will also include retro so we are looking at setting up 400 * 5 eligibilities. I am looking at doing this via HDL, but am wondering if anyone has done anything similar and can warn us of any pitfalls or give