Challenge the sphere again

So far I haven't finished any sphere printing yet, therefore I tried to print again this time. 

Test print 19, fail agian. The side of the sphere warp and cause the nozzle ran into it.

Test print 20, the bottom of the sphere shrank, I'm not sure what's the problem. Could it because of the over hang problem? Temperature of the plastic no even? Size of the sphere too small? But at least I got a sphere looking object, although it looks more like a mushroom.

Test print 21, again the nozzle ran into it. Failed.

Test print 22, the size of the sphere is bigger than Test print 19, I give it a wall to keep the temperature the same I hope i works, and also drive away the nozzle by printing the wall instead of keep moving on top of the sphere, so that it have some time to cool down.

Compare of 2 spheres. I know it can't be compared as they are different size. Just for a record so far what I've tested.