>>23592721That's not a good idea. On paper, it sounds nice. But with one of your moves only being available for 5 turns the opponent can play around it. And you don't even beat Dragons.
My mixed Char-Y is Naive with EQ and Roost. Timid is still good because EQ will still 2HKO Heatran, but I haven't regretted Naive since it's paid off for me in the past with the small roll difference against things like Chansey where I didn't want to risk missing.
If you insist on bumping your Speed with +SpAtk nature, use Flame Charge instead since you're going mixed anyway. Keeps up offensive momentum.