In that case:
You never really need to cap a point. If your fleet is superior, it will end up taking those points anyways unless your entire fleet is nothing but slow ships. If it is inferior, it will end up losing those points anyways. There's barely any middle ground and if you have the skills which does the same thing, the effects of them are minimal in comparison.
The best ships for harrass and assist in PD is just another big ship you can build like your Conquest, Astral, Legion, Odyssey or Cruisers like Doom, Eagle, Falcon, Heron. They can be their own PD. All carriers are essentially range 4000 PD or harrass depending on configuration, with the bonus that they are replenishable in a way that frigates and destroyers are not. Though I suppose it would be the carriers that need the support. I guess Omen and Tempest and telling it to escort can be useful too. There's no real need to use them though, unless you happen to have less than 20 DP to use.
Actually that would make an interesting discussion. Which would be better? 6 Conquests, or 5 Conquests, each with a Tempest Escort? What about omens as escort? Orders?