I need Git. Is it better to install command line tools (183mb) or `brew install git`?
You need the command line tools to install Homebrew anyways, see: 
https://docs.brew.sh/Installation


  Requirements
  
  
  An Intel CPU
  macOS 10.12 or higher
  Command Line Tools (CLT) for    Xcode: xcode-select --install, developer.apple.com/downloads or Xcode
  A Bourne-compatible shell for installation (e.g. bash or zsh)