How many grounds

Hey guys, don't mean to bring back an old thread but I found this from a search and learned that I need more grounds on my car!

Also want to ask since I have aluminum heads on my engine, where would be a good spot to bolt the negative cable for the battery? I have a Magnum block I could probably use one of the threaded bosses for the newer truck engine mounts? Also for the other grounds (engine-to-subframe, engine-to-firewall etc.) what size and type of wire is sufficient?