....what is a "T5 carve"
It refers to the neck profile, or "carve". It is slimmer than the current standard Taylor neck but not as slim as the "Slim Carve" neck. The official response from Taylor is that the T5 neck is similar to the profile of the older pre-NT necks. Personally, I think that the slim carve is more like the older necks - at least more like the neck that was on my 1998 814ce.
The story I heard was that Doyle Dykes noticed that the necks on his older Taylors were thinner tha the standard NT necks and asked Taylor to duplicate those on his newer guitars with the NT neck - and thus, the Slim Carve neck was born.
Here are the specs.

Has anyone noticed, given the tolerance(+/- .025),that a slim and standard carve could have the same measurement and be within "specs"?( .840 - .025= .815 = .025 + .790 .868 - .025= .843 / .831 + .025 = .856)
If +/- .025 is the tolerance for all the machining,I don't wonder that fitting of the neck requires a sack full of shims to get a decent neck angle.
I think uncle Bob needs to tighten up his QC.
Of course,I'm a CNC machinist and my most generous tolerance is usually +/- .002. The tightest I've machined is +/- .0005.
For example, a sheet of 20 lb. printer paper measures .004 +/- .0005. Note: All measurements are in inches

Steve