Well, maybe it would be best to start out with the measurements of the fittings on the actual ship. I'm home now, and have Mr. Campbell's plans in front of me. On the second sheet he was kind enough to include a table showing all the deadeye diameters. They are as follows:
Fore and main lower shrouds - 10"
Fore and main topmast shrouds - 6 1/2"
Fore and main topgallant shrouds - 4"
Fore and main capstays - 10"
Fore and main topmast backstays - 9"
Fore and main topgallant backstays - 7"
Fore and main royal backstays - 7"
Main skysail backstays - 6"
Mizzen lower shrouds - 9"
Mizzen topmast shrouds - 6"
Mizzen topgallant shrouds - 4"
Mizzen topmast backstays - 9"
Mizzen topgallant backstays - 6 1/2"
Mizzen royal backstays - 6 1/2"
How closely must the modeler adhere to all those dimensions? Well, as far as I'm concerned there's nothing a modeler "must" do. That list includes six sizes of deadeye: 10", 9", 7", 6 1/2", 6", and 4". Rationally, few human eyes are going to distinguish between 6", 6 1/2", and 7" in 1/96 scale. A reasonable compromise might be to use four sizes: 7/64" (for the 10" ones), 3/32" (for the 9" ones), 1/16" (for the 7", 6 1/2", and 6" ones), and 3/64" (for the 4" ones). We then collide with the practical reality that Bluejacket doesn't offer all those sizes. A practical solution might be to use Bluejacket 1/8" deadeyes for the 10" ones, Bluejacket 3/32" deadeyes for the 9" ones, and Bluejacket 1/16" bullseyes for the smaller sizes.
The topmast and topgallant shrouds are set up just about alike. In the case of the topmast shrouds, the futtock shroud consists of an iron bar with an eye forged in each end of it. The eye at the upper end is bolted to a little fitting with two eyes in it that passes through a hole in the angle iron rim of the top; the eye at the lower end of the futtock shroud is shackled to the futtock plate, an iron forging with a z cross-section that's riveted to the lower masthead a few feet below the top. The deadeye strop is bolted to the upper eye in the fitting that goes through the top. (Suggestion: for a model on 1/96 scale, bend a piece of wire around the deadeye and shove the wire through the top to form the futtock shroud. Drill a hole in the lower mast to take the lower end of it.) The topgallant shroud arrangement is a little simpler. The futtock shroud again is an iron rod with an eye forged in each end, but this time the upper end of the rod sits in a notch formed in the end of the topmast crosstree and the deadeye strop is bolted directly to the futtock shroud. The futtock band is in two pieces, held together by bolts and nuts; the bolt passes through the eyes at the lower ends of the futtock shrouds.
I think a lot of modelers who undertake the Cutty Sark don't realize how much of her is made of iron. She's actually a fascinating combination of remarkably sophisticated wood- and metal-working.
The Bluejacket "deadeyes with lanyards" aren't bad; the 1/16" ones might, in fact, work ok for such things as the backstays. (Deadeyes on backstays often are set up farther apart than those on shrouds - presumably because a backstay, being a longer line than a shroud, is likely to need more of a range of adjustment. Mr. Campbell shows the topmast backstay deadeyes spaced like those of the shrouds, but the topgallant, royal, and skysail backstay deadeyes spaced slightly farther apart.) I don't recommend trying to shorten those fittings, though. If you get a britannia metal fitting near a soldering iron you'll be confronted with a blob of metal. (The stuff melts at about the same temperature as solder.) And I rather doubt that CA adhesive would work; such lines actually do come under quite a bit of tension (especially when an errant finger bumps into them accidentally). My strong inclination would be to prefer the little bullseyes - which are available in sizes down to 1/16". Few eyes are likely to notice the difference between a bullseye and a deadeye at that size.
One other approach, if you don't want to try making your own deadeyes: Model Expo sells some pretty nice turned wood ones. The diameters stated in the ME catalog are nominal; the actual fittings often turn out to come between Bluejacket sizes. It might be worth ordering one package of each size and comparing them with what you've got.
Oh - I looked up the word "reeve" in the American Heritage Dictionary (my favorite). The definition is: "nautical. 1. to pass (a rope or rod) thorugh a hole, ring, pulley, or block. 2. To fasten by passing through or around." And the past tense is listed as "reeved or rove." Sorry about that.