Damien1307 is spot on his sparkplug choice for him & his location. I'm a firm believer in going 2 heat ranges hotter during the winter. I've recently been using & testing the NGK BR6HIX or #3419 They are a factory preset plug gap at .031" since it's a iridium plug. Your not to gap iridium plugs as iridium will chip off. But with that plug in my 2 stroke it runs great & as good as a standard ngk plug.
But where I've found the NGK BR6HIX plug worth the money is it lasts about 3 times longer & seems to combat plug fouling tremendously better than a standard NGK plug. I'm not saying it's best plug or what you need, but in my testing it has showed me the price difference of it. In longevity.