When was the last time anyone walked out to anything farm or garden and said "gee I wish I wouldn't have built this so big?"
It's always too small...
Especially when it comes to chickens!
I'm also familiar with the oft quoted "minimum standards" of 4 square feet per bird in the coop and 10 in the run. And I also think those are incredibly small spaces for chickens. It's all great and good, until it isn't and maybe birds get stressed and start pecking each other. Those things are far easier prevented them solved. Chickens are naturally busy birds and the more room you can give them the better. They may be flock animals but they also need room to get away from each other when they've had enough.
Basically, you'll not likely to be sorry that you went bigger rather then smaller but the opposite happens a lot.
They will be free range during the dayI think it makes a big difference whether they'll be out to free range by day, or at least, have a large turnout pen.
My coop is on the small side, but they're only in it at night. Let out first thing to run all day.
So what will your daytime setting be?