You probably won't be able to make much of a vertical adjustment on the engine as the spinner needs to be centered on the cowl. You'll need to lower the tank if possible. Don't gauge the tank placement by the fuel outlet height, it's the level of the tank itself that matters. Center of the tank should be level with the carb for best operation. Whether the tank has the outlet in the center or closer to the top doesn't matter, the fuel inside is going to seek it's own level either way.