What type of anchor do you currently have (and rode) and what type of bottoms do you typically anchor in? There's really no "bad" anchor out there - all of them have their pluses and minuses and it really comes down to anchoring conditions and personal preference. I've used pretty much every type out there and I have yet to find one that is just plain "no good". Also keep in mind that not all anchor rollers work (well) with all types of anchors. Some are actually specifically designed for a certain type of anchor.
As noted, the first thing to do is to increase your scope. That's actually the most common mistake people make is that they don't let out enough scope for the conditions. VERY generally speaking, 5:1 is typical for average conditions. Sometimes less, sometimes more. You can TOTALLY anchor VERY securely with just rope, but chain makes it much easier and you don't have to let out as much scope.
I'm not sure about your windlass, but maybe it's the owners/parts manual? I think you can download it from Grady's website. If not, send Grady a note, with your HIN, and I'm sure they can tell you.