either

In dictionary, there are example sentences.
I'm confused. Help me!

-Sightseeing is best done either by tour bus or by bicycles.

I think this sentence means 'by tour bus' and 'by bicycles' are the best ways. when we go sightseeing,we choose just one of them. 'by tour bus' is the best way to someone. 'by bicycles' is also the best way to another.

-There are two types of qualification-either is acceptable.

Likewise, I think this sentence means two types are both possible.
Whatever type someone has, it's ok.

Am I correct??