I was thinking about the
poll.
For the time era :
Why choose? If we can all build countries and cities, we should just choose the architectural style of the area, allowing lots of diversity. And i'm more into modern buildings, so Present seems better. And we can mix styles anyway, for RP , with old towns, surrounded by more modern buildings, or whatever you want.
For the currency :
IC are good. You'll need to disable the crafting (of credits with metal and crafting of higer value credits to a bunch of lower credits, and of lower credits to a higher credit), and spawning in dungeons (but isn't it already disabled?), and use NBT tags to change the tooltip to give them the value you want (the default values are weird... dafuq, Greg), like 1 for the iron one, 0.1 or 0.01 for the cooper one, 10 for silver, 100 for gold, 1000 for diamond. Changing the NBT tag will prevent any kind of counterfeit. Set as tooltip: [value] - Official [name of the country] credit. You'll just need a way to give the NBT modified credits to the bank. I guess this can be done via server pulgins.
Edit : damn you forum. why the posts don't always merge?