Well you have compute earlier the lands for each player which is around 13.
If there is only 1 water nation, a second guy can pick an other water nation and expect 11 water prov + 2 lands prov. (and he has the same average amount of lands than any other nation)
The true problem is only 1 water nation, which unlikely to happen.
And if it happens i ll sacrifice myself and take the 2nd water nation. So don't worry
I also want to remind everybody that you can delete your actual pretender, before the game starts, by sending me a PM. (so some1 with land nation can switch to a water for example, or the 1rt pick of water nation want to change because two others peeps picked after him water nation and he thinks water is too crowded)