I've figured it out! Thanks for the help, self. Oh, you're welcome, self!
Anyone wanting to install OSX services via python will find this useful.
Load the service
servicePath = '/Library/LaunchDaemons/com.myplist.file.plist'
launchctlCmd = ['/bin/launchctl', 'load', '-w', servicePath]
# Execute service load command
proc = subprocess.Popen(launchctlCmd, shell=False, bufsize=1, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
Start the service
serviceName = 'com.myplist.file'
launchctlCmd = ['/bin/launchctl', 'start', serviceName]
# Execute service start command
proc = subprocess.Popen(launchctlCmd, shell=False, bufsize=-1, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)