You HAVE to have two alternates with forecast weather suitable + and - 1 hr ETA if you are departing for a destination that has weather below your mimima.
In fine weather I cannot see the benefit nominating two and taking fuel for two. You could take fuel for a further alternate which would allow you the option to go to a closer one when there are unpedictable weather phenomena such as SN or TS, or just load EXTRA fuel.