Cookster:
Here is some information on shrouds from one of my references, if you want to get anal about these things:
Shrouds on the lower masts at the fore and main in the 18th century were 60% the size of the main stay, and the Mizzen was 40%.
The main stay was about 15% the diameter of the main mast. (Some heavy duty ropes here!)
Reduce the shroud sizes by 50% for the topmasts, and half again for the topgallant mast shrouds.
As a general rule the running end of the shroud was on the fore side of the deadeye.
Shrouds were laid in pairs starting at the fore starboard and alternating starboard then port, etc. The rope went up over the mast, was seized (tied to itself) at the top, then was laid back down to form the next shroud aft on the same side.
If you have an odd number of shrouds, they were either spliced starboard to port, or the running end was seized like the others then stopped at a block which hung near the top of the mast; this pendant was used for general hoisting.
Shrouds, as all standing rigging, should be black as the that rigging was tarred.
Running rigging was not tarred, thus is brown or off white hemp.
Ratlines were rarely used on the togallant masts, and never on the royal poles. They begin above the upper deadeyes and continued to the futtock stave. The lower mast, topmast and lower futtock shrouds all received ratlines. (Futtocks are the short shrouds that go outwards to the mast top; they take the load of the upper mast shrouds.)
Ratline spacing was about 16 inches give or take, and they were light rope or spun yarn about 1 1/2" diameter. They hung loose between the shrouds.
If this is information overload don't worry, I just thought you might like to know how the shipwrights did it in 1:1. Your model will look great if the deadeyes all line up neatly and you use smaller line for the ratlines. I'm sure that anything you do will beat what came in the kit.
Regards,
Bruce