Hello, @Georgie
These are prices from OVH correct.
These are good servers.
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From a technically opinion and look, you can have:
let's say 4GB RAM for each server, so 32 / 4 = 8
You could from a RAM and application perspective you can have around 8 servers. All running at the same time.
Now for 64GB I would say 10 servers, now yes, that doesn't use the same "equation" but, if there was a core and thread increase to accompany the RAM difference, then I would say 16 servers.
Now to also looking at @Warsheep's response, I have ran so many servers on different boxes and even VPS (which are sliced Dedicated Boxes). I would say, to minimize your problems, do one server, and test it, for about a week, just plain vanilla.
Then copy and keep a backup, that you won't run, then paste new servers, and change the parameters to suit each server location and then add each mod that you want and every mission to see if it works.
In @Warsheep words: "Simple test it."