I used a Fx-16 on a pearson 303 and an Islander 32. On both boats it held well in conditions up to the 30 kn range (never anchored in condtions above that). The anchor was never deeply enbedded. I don't know if you have used one before, but I found them a real pain to set - too light. They want to float when you get up enought speed to back down on your anchor. The only way I found to consistantly get it to set, was to let out almost all my rode as I backed and then (with the boat out of gear), pull myself back to the anchor. I still have it and use it, but only in a mud bottom. and as a storm anchor. I use a Bruce now and love it, but a lot depends on the type of bottom you anchor in. I now have a E-27 and think the 16 is probably over kill, but as others have said, it's better to be too big than too small and sleep well.
Bill Hearsey
E-27 Rosscoe