Hi,
The Just Strings (juststrings.com) site has string tension values for many strings from many, but not all vendors.
Over the years, I have heard that a light string set (.012 to .052 or .054) will be anywhere from 150-180lbs.
Medium strings range from 175-200 lbs.
I don't know if I agree with Mr. Taylor. In order for the string tension to try to purely compress the guitar, as opposed to trying to fold it up, the neck would have to have exactly the same angle as the strings. As acoustic guitars need a saddle and a bridge, there will always be some angular difference between the strings and the neck, and this will always create some force/pull upward on the neck (or downward on the soundboard). The angle of difference is not great, and if needed, the forces involved could probably be calculated, but when all is said and done, acoustic guitars will all need a neck reset sooner or later.
I do find it interesting that one of the selling points of the Taylor NT neck is that it is so easy to do a neck reset. If Mr. Taylor's necks are always set perfectly, and according to him, a perfectly set neck will never need to be reset, why emphasize the ease with which a neck reset can be done? It would be a better selling to point to just come out and say that "Our necks will never need to be reset because they are always set perfectly".
Kostas