Question about OSPF in my network

I am in the process of changing many things on our network. Current network has all static routing and we use a L3 connection between our office switches and the switches that are used by the dark fiber network in town. The dark fiber switches then route all data to our main centralized switches where the rest of the routing happens. We are now transitioning to having a L2 point to point connection back to our datacenter switches from our offices rather than this L3 network. I am looking into switching from static routing to OSPF. Here is a network diagram of what our setup will look like when completed.

My thoughts are to setup the network as follows:

• Run OSPF between switches to aid with routing.
• Use a /29 for each of the point to point connections between each office. This is because we have two switches setup in our datacenter that are running VLT + Peer Routing so a /30 would not work as that only allows 2 hosts and not 3 or 4.
• I would like to keep routing table as small as possible.

So my question is about areas. Should all of these switches be in area 0? Or should I leave the DC as area 0 and then create a different area for each office?