@Carnival-Boy said:
So what should I set for cores? 1? 2? More than 2?
Now that gets out of the area of "easy to answer." LOL This comes down to your workload. The rule of thumb is start with one, test, increase, test and repeat. Stop when you start to lose performance and go back to the one that was best.
Not all that helpful, is it?
For a SQL Server, I'm pretty confident that the right answer is not "one". I would start with two and see how it performs. Chances are two is going to be the minimum that you would consider using. Watch those two and see how they are utilized. If load gets high (that's load factor... the run queue length) then more vCPU might be in order. Not super common (by VM count) to go over four vCPU, but there are certainly cases for it.