I'm not sure I understand how breaking up subnets to counties like this is helpful. Is your routing actually hub-and-spoke like you say in the document, with a central router in each county? Do hams in that county connect directly to the central router for routing? Whether BGP, OSPF, or IPIP, I thought the plan for AMPR was do use mesh routing.
I've seen a case in AMPR where addresses were pre-allocated geographically instead of by network.
That was done in Montana 20 years. It was a nice idea but functionally it did nothing but give me far too much experience in routing bits and pieces of the network on X1J nodes. We should have focused on actual live LAN's - networks in actual operation - and used the IP allocations to serve the users on the air.
73 Bill, WA7NWP