I admit that I haven't been looking that closely at IV and it was mostly a 'feels' thing. So I read a bunch of links from the OP and am still convinced that IVs aren't worth the effort.
Let's start with a 500 CP Charizard (
Charizard | Pokemon Go).
It'll take 147,600 Stardust + 122 Charmander Candy to get a 500 CP Charizard to 2000 CP.
147,600 Stardust is months worth of playing. You only get 100 Stardust per Pokemon catch, 500 Stardust a day per gym, and 2,000 Stardust per 10km egg (couldn't find the numbers for lower distance eggs, assume less than 2,000).
What about the benefit? If we scale Charizard to about 2000 CP, it??Tll be level 33 can have 2008.07 - 2343.09 range in CP. The midpoint is 2175.58.
Pop the numbers in an IV calculator (
Pokemon GO Tools | The Silph Road) and you??Tll find that it??Ts only a 21 attack + defense IV stat difference between the 50% and 100% Charizard, given both have the same HP/Stamina.
Charizard??Ts base attack + defense are 212 + 182 or 394 combined. Therefore the 50% Charizard will have 403 stats and the 100% Charizard will have 434. The 50% Charizard has 92.8% of the attack/defense of the 100% Charizard.
For the amount of effort in getting the Stardust and Candy, I??Tll stick with the 50% Charizard with the higher CP.