I wouldn't call a stern anchor a kedge - as I tend to think of a kedge anchor as a hook set out just to pull you over when aground. I would think of what you're doing as using a stern anchor in an attemp to rotate the boat such that it doesn't lay beam-to the incoming swell.
For handling rolling in swell I will usually look for somewhere else to anchor, for starters. If there's nowhere else around to go, then I will sometimes put out a flopper stopper - I have a Forespar version, it works fine, so do the plastic platic kind, the ones that I've heard do not work
are the bunch of cones in a vertical line - and that dampens the swell.
For running two anchors, I like to Bahamian moor with both rodes lead up to the bow roller (this is where the set and retrieval is done from. If there's room, I'll set the main anchor, pay out rode
to where I want the stern hook to go, drop the stern hook and pull back in on the main anchor to position the boat between the two. To do this, I have a lot of rode: 275' of chain backed up with 300' of nylon rode on the bow, and 50' of chain with 350' of nylon rode on the stern anchor. You do need to have an overly long rode on each anchor to work this way, and a fair bit of room to maneuver in while setting the hooks.
In a tighter area it's nice to use the dingy to set the stern anchor, as you can direct the dinghy
to be exactly where you want it to be and then let go the anchor.
In the US Pacific Northwest
it's common to see boats with a 600-1200 foot spool of polypropylene line (it floats) mounted on the stern rail. The bottom can shelve off so rapidly in some anchorages
that it can be difficult to set two anchors - so the main anchor is set well, then the dinghy
is used to run the spool line from the transom to shore, run it around a tree or log and back out to the boat. If all goes well, you can retrieve the stern line in the morning by casting it off from the boat and pulling it all the way back around the tree without having to go ashore. Sometimes that doesn't work and you have to go get the line by hand... Having the line stored on a spool sure makes it easy to use the next time you need it (and keep a sunbrella cover on the spool when stored to retard the rate the sun burns up the polypro).
Oh right - rolling hitch is a good way to tie onto chain with nylon, much better to my thinking than a chain hook, as the nylon won't tear up the chain's galvanizing the way a chain hook can.
And Gord's mention of side-tying to the anchor chain is right on, though I've only tried it perhaps twice and each time not for long.