There are so many good ideas. Everyone has their own preferences and each has merit.
Our calving sheds have 10'x10' stalls and I think that is a good size. Not too big, yet big enough to give the cow room to move around without endangering the newborn calf. However, Soapweed gets along good with 8'x10' pens, so if you want to maximize the area of your barn, I'd go with that.
In our case, we have pens down each side of the barn and a long alley in the middle with gates that let us divide the alley in four large sections. I like to leave the cows in the alley sections to calve, then move the pair into an individual pen. This tends to keep the pens cleaner and the larger area gives the cow room to pace around. If necessary, you can put two or more cows in each alley section, again moving a new born into a pen after birth.
We made short calf hooks out of 3/8" rod to pull a newborn with. they are about 3' long and shaped like a typical "shepard's" hook with a D-handle on the other end. We keep several in each shed so you never have to go very far to find one. We have a firm rule though, to always put it back in the same place because they can get misplaced easily otherwise. If you hook the calf above the hock, it's easier than down by the hoof.
One shed is used only for penning pairs. The other one not only has individual pens but also has our pulling pen, heated vet/storage/wash room (with hot water) and tack room, etc. We normally take heifers to this barn to calve in case she needs help. If a cow needs assistance from the other barn, it is simple to move her through an alley that connects the two sheds. We keep a folding cot in the vet room that lets a guy stay out with the cows all night if bad storms make it necessary.