Time to upgrade: Thuringian or Zulu?

I am interested in buying a finishing stone for my routine touchups on razors.

I regularly use my Nortons for honing up to 8k and then the Chinese stone which was proved to be a very nice finishing option and I am very happy with it.

I think now it is time to upgrade my finisher. My new stone will be used mainly for touching-up the razors after 8-10 shavings.

I have read many posts on the hones’ section and I am between choosing the Thuringian or the Zulu grey.
Which one of these would you recommend for fast and quality touchup?

Thank you in advance for helping.