Honestly a shared dropbox client with your Engine&Editor folder would, in my opinion, be a faster and less hassle free way to collaborate.
As for Hamachi, it should be a pretty straight forward setup, Run your Hamachi server, Copy the public IP, change the <HOST> in your client resource folder to your public Hamachi IP and send the Client folder to your pals and bam, you & and your friends should be able to connect. Though i'm not sure about the port when using Hamachi so that might be something you need to play with I.E open the default Intersect port 4500 on the system that you are running the server from.