I would guess that its not very much internal adjustment. The 419 rail is going to cost you as much as the scope is worth.
I would seriously look at something that is a little more quality for your CZ. About the cheapest I would even consider, as you are obviously planning on dialing elevations is an Athlon Argos or Vortex Diamondback tactical.(at least they have a decent track record in CRPS and great warrant if you do break it)