Some questions on character

How should I manage mastery bar - let’s say shaman / soldier, at level 85 should both mastery bars be maxed out or just 1 or 1.5 - how should this work? You can’t mess this up because it is not refundable, so I ask the community.
Do you get more points from soldier or shaman or are all classes the same?

Depends on the build. There are builds which go 50 into both classes. There are quite a few that go 50/32 or 50/40.