I'm one of the biggest HxH fans on here and even I think its crazy that people want the anime to go past the election arc knowing it will catch up really quickly and probably won't even be done for a few years.
End at 339 with the scenes and some added to the full version of the opening (something I called last year before everyone else BTW) and leave off with a small cliffhanger like showing beyond netero announcing the voyage for the dark continent or something and end there. Its a perfect way to close the series and leave just enough room open to be continued later (which is what Togashi did) we'll probably have some new anime material in 2 or 3 years from now after this.