what's better for hex pult? wisp or twave
depends on the team, but I personally would go for Thunder Wave, as it hits more targets, such as Heatran and Volcarona. Thunder Wave can punish these two Pokemon very well, with securing, that Heatran can't fullfill its role anymore, and in Volcaronas case, it can struggle to turn into a deadly sweeper altogether, as a paralysis rips it off its speed as well, which Volcarona needs to sweep lategame. So I would go with Thunder Wave at the moment, as Heatran and Volcarona are very relevant targets. Furthermore it can help out against Clefable and force some paralysis here and there.
hope that helped :)