I think 1 account is OK, because you can manage several sites by using 1 account, it's no need to use 2 accounts.
Google webmaster considers only one account for one website. Webmaster is not allowed one account for two website. Let’s create two accounts, it is the best option.
you can use as many websites as you wish in one single account.. There's no need for additional account.
What is your purpose by using 2 accounts really? One account can handle unlimited websites. You can use two account if you want but Google is still know those 2 accounts are under the same roof.