Should I upgrade my th to level 11 so I cant get additional barracks total of 4? I have 1500 might and should I also upgrade the centaurs or not?
As far as your might is concerned you're fine for being a smurf, just dont upgrade your druid too much or he'll boost your might quite a bit. I substituted having upgraded troops and camps instead of getting 5 heroes, I don't feel like it's necessary for me to have super powered heroes.
I leveled camps because they help tremendously in raids. 50+ level 5 centaurs and 3 late level 60 heroes coming at you in a massive wave at 2k might is devastating. My raids end in as much as 10 seconds with no losses most of the time.