SEO on Rails or Rack

rewrite.rb

# As a general rule, I despise all things SEO with it's witchery and voodoo ways.
# However, these two practices are confirmed semi-non-witchcraft SEO best practice.
#
# 1. Serve your content from a consistent domain (www vs. non-www, Doesn't matter. Just be consistent)
#    In addition this is nice for Heroku and other cloud based deployment environments that leave your app 
#    accessible from a url like http://myapp.herokuapp.com
# 
# 2. Believe it or not, trailing slashes matter. The google machine interprets http://domain.com/about 
#     as a different page than domain.com/about/ 
#    (source: http://googlewebmastercentral.blogspot.com/2010/04/to-slash-or-not-to-slash.html )

# https://github.com/jtrupiano/rack-rewrite

# Gemfile
gem "rack-rewrite"

# config/environments/production.rb
config.middleware.use Rack::Rewrite do
  # SEO Rewrites
  # - Consistent domain
  r301 %r{.*}, "http://my-domain.com$&",
    :if => Proc.new {|rack_env| rack_env['SERVER_NAME'] != "my-domain.com" }

  # - Remove trailing slash
  r301 %r{^(.+)/$}, '$1'
end

Does anyone have an opinion on the best place in the middleware stack for rewrite rules? I'm thinking it could be the first middleware before Rack::Lock