I was able to get Fast Lane installed by following
However, I was never able to get any response at all from running 'which fastlane' in Terminal (it didn't fail, it just didn't output any text)? But, I could see from my terminal installation log that everything seemed to get setup properly.
I stepped thru https://blog.xamarin.com/easy-ios-app-provisioning-fastlane-visual-studio-mac/ and everything seemed to work with creating a new Project. It setup my certificate for my Mac Pro and what appear to be two identical provisioning profiles the the 'new app' I just created.
However, when I got to the 'Provision a Device' section - I connected an iPhone that VS Mac had never seen (or Xamarin Studio, for that matter) using a lightning cable. The device was not associated with any provisioning profile, but I never got asked (as outlined below)?
If the device attached is not associated with the provisioning profile selected, Visual Studio for Mac will suggest you provision the device. Click Register, followed by Add, and Visual Studio for Mac will add the device to your Apple developer account and associate it with the selected provisioning profile.
What obvious and trivial step have I ignored?