I would opt for the three very strongly. One line size system is NOT much variance. You can fill the gaps in your quiver later.
It was not our intended target, but we have landed steelhead to 12+lbs on a three wt. Rooster fish to 6#, stripers to 8#, halibut to 8#, yata yata. Learning to fight a fish with the butt of the rod and taxing your tippet to it's fullest, works wonders and provides the short fight/quick release desirous for many.
.....lee s.