Bisky was giving Gon emission training while Killua recovered from his damaged hand in GI. If attack range was the issue, telling him directly should be more effective. This seems to be something that the kids have to "realise" and apply right away - she also said tonight was the last chance. Emission wouldn't be something they'd simply figure out.
If it's not Isuzu-chan Mii~
Considering he's following the same path as Uvo, things like an attack range aren't necessarily anything that really needs discovering or thinking. He can simply pick up a rock and throw it at a speed of 800 m/s. It would deal with any opponent that wouldn't need an awesome, thrilling fight.