I had to look it up, seems nice! I saw that coop floor space, not including nest boxes, is 32"x59", or 3'x4.9' which gives you roughly 14+ square feet of interior floor space, almost 15, not including nesting boxes. If I'm right on the sizes, I think you would be okay with 4 hens. I know it says 12 on the web site, but they always overestimate. The general rule you'll see often here is 4sq feet of coop per bird. It helps keep everyone civil. Hopefully someone who has this model will chime in.
My temporary coop, which houses my 4 hens, is 3'x3', not including nesting boxes or run, and is waaaaay too small for my fat fluffy butts. They broke the ramp in a couple weeks. It's only temporary, as we couldn't take their big one with us during the move, but I'm really not happy with them in it. I let them out regularly to try and compensate. Thankfully they are calm and kind to one another, but we can hardly wait for the big one to be finished. Mine also has a slide out poop tray, but it is rather shallow. If I don't clean that every other day or so, it's a mess. We are building a walk-in because I hate contorting myself trying to clean coops, but this design works well for others.
That said, I like the look of yours. It has a decent sized run and wheels, yay fresh grass!
Let us know what you decide.