Calista has 6mm chain – and has had this size from new. The original chain was 120 ft long. Whatever size of chain / warp that you carry recovering it in strong winds or tides can be really difficult – so I am strongly in favour of having an anchor winch / windlass. Because I fitted a winch I had to buy calibrated chain and bought 160 ft of it.
Bearing in mind that you need at least 3 x depth of water as an absolute minimum for chain, (5 x depth in strong winds) that allows me to anchor in a reasonable depth. Up to 60 ft at high tide which at worst gives me 20 ft at low tide (with a 40 ft rise and fall in the Bristol Channel). At worst I can anchor in 32 ft of water – and should still be afloat at low tide in most places where the tidal range is less than in the Bristol Channel.
I dont like rope for my main anchor cable – really because the chain self stows in the original locker which is right below the winch. The winch has a rope chain wheel on it but you cant get rope to go down into the locker – just does not work. You are also supposed to allow 7 x the depth – which is a lot of rope to handle! So with 120 ft of rope you can in theory only reliably anchor in 17 ft of water in strong winds – and the boat will sheer all over the place!
For a kedge I have 30 ft of 6mm chain and 120 ft of nylon rope. It isnt stowed ready for instant use – but can be rigged fairly quickly.
Incidentally I carry 3 anchors, the original 15lb danforth which came with the boat when new, a 15lb CQR, and an 18lb fisherman.
The danforth is usually on the end of the chain ready to let go, the CQR stowed on deck and the fisherman below deck. Different anchors have different properties so just one isnt really sufficient. For example the CQR drags for some distance before digging in so is OK as the main anchor – but not much help as a kedge (it drags all the way back to the boat before digging in). The danforth digs in almost instantaniously so is brilliant for a kedge. Both of these are good in sand and mud, but not much use in stones or shingle. They dont get through kelp either. On the other hand the fisherman is brilliant in stones, kelp and rock – but you take a risk on it getting stuck in rock! You would not want to use the fisherman if there was any possibility of drying out on top of it either!
I suppose having written this much I have to make a final comment on tripping lines. Lots of people use them – but I have rarely had an anchor stuck in anything. However I have always found a tripping line a real pain, tangling in the cable, round the anchor, in the keels etc on the few occasions I have used one. So I NEVER use a tripping line!