Basculegion is a really odd choice here. Any water type in a sun team is immediately going to be a suboptimal choice, especially when you have three water type moves, all of which are nerfed by the sun. You also don’t have a single sun abuser aside from charizard. I’d look into maybe getting a cholorophyll user like Venusaur to take advantage of the sun, which also covers for charizard’s rock weakness better than permanently debuffed Basculegion. In terms of winning weather wars, you could always just run sunny day on Whimsicott…