you only get points from the team that would award you the highest amount of points.

Only 1 team !

5v5 offers best points / rating, as 3v3 is points -10% and 2v2 is points -20%

ie, say 1500 rating would give you 300 points in 5v5

then 1500 rated 3v3 only gives 270 points

And yes, greens and blues + arena means you WILL get splattered all over the floor. For starters, the opposing team has approximately TWICE as many hitpoints as you do (my hunter has 13.6k hp unbuffed for arena) and your crits are +20% lower due to their resilience...

Dont worry, as suggested above, 10 games pr week, and keep running battlegrounds non-stop for offpieces first (guardians preferred, else just get vindicator pieces if you can't gain any rating).

For arena-points, go for the Guardian Gloves first, as they dont require rating, and are only 1100ish points.