Since this thread is so interesting, and so friendly, I'll go one step further and offer an opinion (with which, of course, anybody is free to disagree) on the subject of "preformed ratlines." I suspect nobody will be surprised that I intensely dislike them. My custom was always to throw them out before leaving the hobby shop (back in the days when I could buy ship model kits in a hobby shop). I'll cheerfully concede that the plastic-coated thread ones are preferable to the monstrous injection-molded variety. but that's not saying much.
Three reasons. One - they're almost impossible to set up tightly - and the shrouds (except on the leeward side when the ship's working to windward) should be very taut. Two - they're invariably made in such a way that the ratlines are the same diameter as the shrouds. (In a real eighteenth-century ship the shrouds are among the largest ropes in the ship. In addition to keeping the masts from falling over, they're key components of the propulsion system. The sails pull the masts, the masts pull the shrouds, and the shrouds pull the ship through the water. The ratlines, which only have to support a man's weight, are much thinner.) Three - there's no good way to secure the upper ends of them. (In a real ship, the lower shrouds were looped around the masthead one after another. They were also parcelled and served - i.e., wrapped with canvas. The stack of shroud eyes on board a ship like the Constitution would rise a quarter or a third of the way up the lower masthead, and the eye of the stay would be passed around them. Those piles of eyes are quite conspicuous in pictures of the real ships - and contemporary models. Theyre's just no way those manufactured concoctions are going to look like that.)
The manufacturers seem to have convinced several generations of modelers that the shrouds and ratlines on a plastic ship model just have to look phony. A well-kept secret: rigging ratlines to scale is easy. (Rigging shrouds, with individual deadeyes, is another matter. I find that one of the trickiest jobs in ship modeling.)
For what little it's worth, I can summarize how I did the job on my little model of the frigate Hancock (scale: 3/32"=1'), which is shown in my avatar. I started out by making the rope for the shrouds, using silk thread on my primitive "rope making machine" - spinning the strands counter-clockwise to reproduce the cable-laid (or shroud-laid) rope that was usually used for that purpose in those days. After seizing the eye in the middle of each pair of shrouds, I coated the eye with some stuff called "modeling paste," which I found in an art supply store. I mixed a little black acrylic paint with it, for color. Then, taking an educated guess at the finished lengths of the shrouds, I seized the deadeyes (britannia metal castings from Bluejacket) into them. The lower deadeyes were already in place on the channels. Then came the lanyards between the deadeyes; for them I used the finer of the two diameters of silk thread that I had at the time. This, to me, is the trickiest part of the rigging process: getting the upper deadeyes lined up in a row that's parallel to the channel - with a 3-diameter separation between uppers and lower. If you screw one up, you have to make a new piece of rope.
For the ratlines on this small-scale model I used a spool of .003" nickel chromium wire that a hobby shop friend (ah, nostalgia!) had found in a military surplus store. That turned out to be great stuff for th purpose: soft enough to be tied in a clove hitch, but stiff enough to be tweaked so it sagged a little between the shrouds. To establish the spacing, I cut a piece of file card to fit between the channel and the underside of the top, inside the shrouds. A series of inked lines, 3/32" apart, established the spacing of the ratlines. After the nastiness of setting up the shrous and deadeyes, rigging the ratlines was easy - at least for a pair of 30-year old eyeballs. I honestly don't know whether my current 62-year-old ones would be up to it or not.
The key to rigging ratlines authentically is practice. The muscles and nerves of the human hand have memory, and can be taught to do remarkably sophisticated things if given a little time. Set up your little card with the parallel lines on it, put some nice music in the CD player, and have at it. My guess is that the first ratline will take you about fifteen minutes. But by the time you get to the masthead you'll be rigging one every two or three minutes, and wondering why people make such a fuss about ratlines.
Some people, of course, lack the closeup eyesight and/or manual dexterity to do such things. I deeply sympathize with those folks; I had a mild bout with arthritis in one hand a few years back, and got a little taste of what it's like. The most cordial, honest advice I can give such people is to pick another hobby. They probably won't get much fun out of ship modeling - and fun, for most of us, is what it's all about. To those who do have the necessary attributes I say: give authentic ratlines a try. If you can do all the other tasks involved in building a model, you can do this, and few improvements to a kit will make such a big difference.
Too long as usual. I've been using this computer time to relax after planting a pair of hibiscus bushes (Mother's Day present to my wife.) Sorry.