That article only concerns it self with core size and core to wrap ratio because it is dealing with how much pitch change is caused by a particular amount of string stretching by a tremolo. All that is over-complex and unnecessary for basic string tension calculations.
All you need is here
http://www.daddario.com/upload/tension_chart_13934.pdf
The most useful document i have ever discovered
T = (U * (2 * L * F) ^ 2) / 386.4
T tension, in pound-force (lbf), often written and referred to as 'pounds' (lb)
U unit weight, in pounds per inch
L scale length of instrument, in inches
F frequency of open string, in Hertz
'Tension' is the required stretching force applied to the string by the tuner in order to raise frequency to the desired 'F'.
'U' is found by cutting the longest possible length of full gauge (with no silk wrap and not including the thicker anchoring section near the ball end). Weighing and dividing by the length.
This equation is what D'Addario, Kalium and GHS all use to calculate the published tension values, they calculate tension from weighing strings and knowing 'L' and 'F'.
Note that core size, core to wrap ratio and materials are irrelevant, only the total unit weight matters.
