splitting CO2 from one regulator to two tanks

[Starry]

I'm about to order a CO2 system, and after much thought I decided to go with the GLA Choice package. I only have a 10-gal tank right now, and there's a possibility I may be getting another tank eventually (either that, or selling the CO2 system and getting out of the hobby for good, lol). Will it be relatively easy to upgrade the parts with a manifold and extra needle valve, or would it be better to just pay upfront now and get it included? In other words, will any of my current equipment become redundant when I want to make the change, will any of it become a waste of money? Or will it be just a matter of addition of parts? I'm really not mechanically inclined, so at this point I just need a quick answer so I can decide which to purchase. Of course I'd prefer not to pay the extra $90 now if there's no advantage to it. Thanks so much!

PS: I might also be convinced to buy the Primo instead of the Choice, if someone can make a very good case for why the NV-55 needle valve is worth the extra $35. But the Primo + dual manifold is out of the question. So I guess my question is really would you get the Choice Dual, or Primo Single, or is the Choice single good enough and easy to change to dual later on?