I am really hoping to get honey this year but if I do not there is always next year.
When you are just starting out you don't have any resources like drawn comb so the hives are slower to expand and they also consume honey to draw the comb. You could have a banner year where your bees store enough for you and them but that is a lot of hoping. It is better to leave them too much the first year then to take a shade more than they need otherwise you start all over again next year. Supers are usually not static. The bees store in them when there is plenty of nectar and consume it when there isn't. It is hard to predict that cycle in the first year.
This is the part that isn't made clear to us new beeks when we're starting. Drawn comb is so important for honey harvest. And it takes so long for the girls to draw foundation. So unless you feed, feed, feed your little nuc and keep them working on comb for next year, next year's flow will be half over before they get a box drawn. *sigh*
To the OP, I'm 38 and wear a brown uniform during the day, so lifting and carrying is no prob. The issue with bee boxes is that you have to hold them out perpendicular to the ground and carefully put them down on a hive of bees. So if you can afford the extra gear for the same box volume, it's probably worth it to go smaller. I'm a second -year, and have allowed these guys to talk me into all mediums. A medium box full of honey held out perpendicular is heavy.
