Calcs looks good to me. Knowing subnet calcs is like eating vegetables, after a while, you start to like them even though you started off hating them. 10.x.x.x is good for ClassA large networks. 192.x.x.x is not the typical Network address you would use for a LAN. It is 192.168.x.x. Why do you feel 10.x.x.x is narrowing it down too much when 10.x.x.x has the same amount of hosts as 192.x.x.x which is over 16 million.

I would simplify it some more if you can and instead of breaking it down to a few IP's per subnet just use 10.1.x.x and 10.2.x.x. Put 250 subnets under 10.1.x.x and the rest under 10.2.x.x this way each location has its own class c address. They call up with a problem and say its 10.0.0.88 you're net gonna know where that is but if they say 10.1.20.2 you have a better chance of figuring it out, makes it easier on documentation to have network.network.network(location).host and leaves room for more hosts in the future.