I believe (memory)that we have a 20kg Rocna on our bows, which is to be considered operation overkill, however we are in Greece, live on the anchor and do have some fearsome, sudden winds. Last year we had 80+ (see Youtube Vliho storm) – we did not budge. Anyway the anchor does fit on the bows of our 331. I should add perhaps that we also have 80m of 1mm chain and that does help.
As for judging cost effectiveness – it depends whether you want to go to sleep. Anyway, I am sure there must be a cooperating dealer amongst the bulk buying contacts. Even Yachtmail give 10% to clubs.