Since Gon's page is still locked and no final decision has been reached despite us commenting on OPN's related blog, I'm forced to write this here.
I have recently expanded the decriptions of Gon's Nen abilities in the template. What however is still missing is Gon's technique called "Aiko" (translated as "Round 2" by Viz), from chapter 209, and later mentioned again in chapter 211. Gon uses it against Knuckle to use two of his Jajanken abilities in quick succession. Its exact mechanics are explained in chapter 211: Gon builds up twice the normal amount of aura for a Jajanken attack, so he expends half for the first ability and then half a few seconds later for the second. It failed against Knuckle because when he used it, he reached 0 P.A.P. and passed out, but that's how it works. It's not really an ability, it's more like a loophole in Jajanken in general, so I think we should just add it to the Nen section.
As for the correction I mentioned, Gon's page says "as per Knuckle's calculations, in their final showdown Gon could use efficiently only 12.5% of the aura he summoned." This is not exact. That percentage was reached by using the estimations Knuckle provided in chapter 211. However, since he was referring to the Round 2 technique, half of the 4000 aura he mentioned were intended for Rock, so only 2000 were destined to Paper. In fact, earlier he mentioned that the two attacks consume the same amount of aura, which, still according to him, is about 2000 aura. So Gon can efficiently use only 25% of the aura he summons while using Paper; 12.5% referred only to the total amount of aura used, Knuckle was saying that, due to Gon having used the technique too late into the fight and passing out, he had consumed 4000 aura, but in the end the only attack he used had the force of a 500 aura attack.