Where to Cut Top??

People have said its a good thing to have more than one stem coming out of soil?? This right?? But I have seen quite a few pics on here, an they are alot thicker than mine at same stage??

And....

The pic of the top of my plant, 1,2,3, ha.. where should I cut??

I have already trimmed bottom branches, even though the leaves werent dead, this is right ye?? to push more hormones upwards??

They are just over 2 weeks old..

Also some of them seem to be touching, is this ok?? Am sure I read somewhere they are not meant too??

Thanks people..