Ideally, any method of reproducing shrouds and ratlines needs to take several things into account. The lines need to be round (which photo-etched metal products aren't), the ratlines need to be considerably smaller in diameter than the shrouds, the shrouds need to be taut, and the ratlines need to sag between the shrouds. The shrouds also need to vary in diameter according to their location in the ship's rigging - the mizzen shrouds should be finer than the main shrouds, the topmast shrouds should be finer than the lower shrouds, etc. All that creates a tall order for any manufacturer. To my notion, none of them has yet pulled it off. On really small scales photo-etching just might work - provided the designer was willing to use the "relief" technique to make the ratlines thinner, in all dimensions, than the shrouds. But to my knowledge no manufacturer has yet tried that.
As in most aspects of scale modeling, there's no real substitute for "doing it to scale" - i.e., clove-hitching the ratlines individually to the shrouds. Here's a link to some photos of my model of the Revolutionary War frigate
Hancock: http://gallery.drydockmodels.com/album194 . The shrouds on this model are silk (cable-laid, made on a crude "ropewalk") and the ratlines are nickel-chromium wire, about .002" in diameter. I'm pretty satisfied with the result.
That model is on the scale of 3/32"=1' (or 1/128). For my fingers and middle-aged eyeballs, that's about the smallest scale on which it's practical to tie the ratlines individually. (I might be able to do it on 1/16"=1'; frankly I've never tried. I certainly wouldn't do it on a smaller scale than that.)
If I were doing that Revell
Flying Cloud I'd use one of two approaches to rigging the ratlines. One - the old "needle-through-the-shrouds" method. Rig the shrouds first (a good idea in any case). Thread a needle with the very finest thread you can find. Make a white cardboard template (index card stock works fine) with a series of lines ruled on it at the spacing of the ratlines (about one scale foot), and slip the template behind the shrouds. Grab the first shroud near the bottom with a pair of fine tweezers, and shove the needle through it. Repeat with each shroud in turn. Touch the end of each ratline with a tiny drop of white glue, let the glue dry, and trim off the excess thread. It's an old technique, and one that works quite well; I've used it, and seen it applied pretty effectively, on scales down to 1/32"=1'.
The other technique is to rig the shrouds carefully and leave the ratlines off altogether. That approach actually has a lot to recommend it. A real ratline is little more than half an inch in diameter; in 1/232 scale (that of the Revell
Flying Cloud) that's smaller than what lots of people can see. One school of thought in model building says "if you can't make it to scale, leave it off." Omitting the ratlines arguably is preferable to making them grossly out of scale.
One aspect of all this that frequently discourages newcomers is the "learning curve." In ship model rigging the learning curves are pretty steep - but short. If you've never rigged ratlines with the "needle-through-the-shrouds" method you'll probably find it frustrating at first. It may take ten minutes to rig the first ratline, and you'll look at the total number that have to be rigged and conclude that you won't finish it before you get so old that your eyesight goes. But if you stick with it you'll discover that the fifth ratline goes a lot faster than the first one, and by the time you get to the top of the mast you'll be rigging one ratline per minute. And I can almost guarantee that when you see the results you'll think they're worth the effort.
The kit manufacturers seem to have convinced generations of modelers that rigging ratlines is difficult, if not impossible. It really isn't. It takes a certain amount of time and dexterity - but so do plenty of other jobs in building a ship model. A model of a full-rigged ship can be "rattled down" in about a week of evenings. One of the most important features of my workshop is a decent sound system. The first thing I do when confronting a set of shrouds and ratlines is to put on a good CD.
Too long as usual; please forgive the rambling. Good luck.