HF buffers are good enough, they sell several different levels of performance.
Get the hook and loop pads in wool and foam, wool for faster cutting, foam for a higher gloss.
Use a multi step buffing compound system. Fast cutting products won't yield as high of a shine as polishing compounds.
Not all gel coats buff out in the same way, some only require a quick buff, some need to be sanded, and on others nothing will make it look good again.
Do a very small area first to determine the exact method needed to achieve the desired result.