Three strand laid line is this:
Double braid lines usually look like this:
Single Braid lines usually look like this:
Notice the heavier strands in the single braid and three-strand laid lines.
BTW, laid lines should only be coiled clockwise and have a twist added to form a neat coil. The twise also helps prevent them from hockling and kinking when you uncoil them.
Braided lines should be coiled in a figure-eight type loop so that they don't get twisted up when you uncoil them.
How are you measuring the lines? You have to measure them when the line is not being stretched and not being compressed. I would guess you've got 3/4" lines. Given the weight and length of your boat, I'd recommend getting 3/4" dock lines at a minimum. Ideally, you'd be better off with 1" docklines for storm conditions and such...but they can be hard to handle.
I wouldn't buy docklnes from WM, even at 25% off..since they're very expensive compared to other retailers. I'd recommend using RWRope.com in New Bedford, Mass., instead. They're much more reasonably priced and have a much better selection. Talk to Paul down there and tell him Dan with the Telstar sent you.
BTW, double braid lines are nice for cleats and such, but the three-strand lines are better if you're tying up to pilings and such, since the rough surface tends to pick the strands out of the double braids more readily than it does three-strand lines.
You'll probably want some 25' lines for breast lines, 35' lines for bow and stern lines, and 50' lines for springs lines. I'd recommend color-coding the lines so you know what length a line is just by looking at it.