Fortress Marine Anchors
Fortress Anchors - Safe Anchoring Guide
I use 10m of chain with a FX7 for a light 24 foot yacht on soft bottoms, the extra chain is because I anchor around coral and need to keep the nylon line off the bottom.
If your anchoring on rubble or weed then a heavy anchor and tackle is more appropriate. Generally locals in an area can give good advise regarding what works best in the area your cruising.