I’ve been using a Lewmar on my 30 Classic for around 20 years – pretty sure it’s a 10 kg. 6 kg would be too light. I anchor quite a lot, and it has never let me down yet. The Danforth type the boat came with from new was pretty useless so I replaced it. There is a trick to stowing the Delta in the bow locker: put it in shank first with the anchor upside down, so the rear flukes rest against the inner sides of the hull on either side of the stem, and the base of the anchor head is facing upward. The chain shackle end of the shank is at the bottom of the locker. The whole assembly is upside down, and it fits in snugly. As for resting on the bow roller, on my bow roller it sits quite happily with the crook in the shank sitting on the roller. If you pull it further astern, then yes, the tip of the blade would foul the hull, but no need to do that. But I only have it on the bow roller when about to anchor, at other times it is in the locker. Much better there.