This website helps me out every time I want to know something about mesh bodies and heads:
http://meshbodyaddicts.com/mesh-body-reviews/
Plus check out the mesh body addicts sim. There are bodies there that already have the alpha built in. I love the Tonic ones.
I use Tonic, eBody, Belleza, and Maitreya. I use a Catwa head but frankly I am having loads of problems with the heads. I keep reading, watching videos, and ask loads of questions of people that I know in game.
Good luck,
Jynelle