Debian Programming :: Virtualenv - How To Default To Python3

I have a few questions regarding virtualenv and virtualenvwrappers. The following packages are available, I am currently using python3 for my project. However I would like have the option to use either 2.7 or 3.x for my virtual environments.

Given this do I install both python-virtualenv and python3-virtualenv? What is that third package all about, does virtualenv support both versions by chance? I chose to install both python-virtualenv, and python3-virtualenv (not sure if both were actually needed). These packages where installed via apt-get.

python-virtualenv - Python virtual environment creator
python3-virtualenv - Python virtual environment creator
virtualenv - Python virtual environment creator
virtualenvwrapper - extension to virtualenv for managing multiple virtual Python environments

So far so good, "virtualenv test" creates a python2 env, and "virtualenv --python=/usr/bin/python3 test2" creates a python3 environment.

After installing virutalenvwrapper (also installed with apt-get) is where I hit the problem. In an attempt to default ot python3 I added the following to my .bashrc file.

export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3
export WORKON_HOME=$HOME/.virtualenvs
export PROJECT_HOME=$HOME/Projects
source /usr/share/virtualenvwrapper/virtualenvwrapper.sh

Sourcing the .bashrc file cases the following error. What am I missing here?

/usr/bin/python3: Error while finding spec for 'virtualenvwrapper.hook_loader' (<class 'ImportError'>: No module named 'virtualenvwrapper')
virtualenvwrapper.sh: There was a problem running the initialization hooks.

If Python could not import the module virtualenvwrapper.hook_loader, check that virtualenvwrapper has been installed for VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3 and that PATH is set properly.

Further searching found a post on stackoverflow which led me to change the .bashrc to the three lines below. After this change it all works!!!

export VIRTUALENV_PYTHON=/usr/bin/python3
export WORKON_HOME=$HOME/.virtualenvs
export PROJECT_HOME=$HOME/Projects

Finally the commands for the two versions of environments.

Python3 (default) "mkvirtualenv test"
Python2 "mkvirtualenv --python=/usr/bin/python2 test2"