I don't have that particular razor, but I read on another thread that it was a more aggressive razor than expected and a forgiving blade such as an Astra SP or Gillette Silver Blue is recommended.
My preferred blade in the RazoRock TTO is the Personna "Red". I get the UK packaging, fwiw, and after reading several dozen threads on these blades around here I'm not 100% convinced that all packages are exactly the same blade, but I haven't tried any of the other "styles" of the Red either...
But for your question, this is far and away my favourite in that razor, and I've tried out most...ended up being a 100 blade purchase for me, my first.
Also edit to add, that the other razors I have - the EJ89 and a Fatboy - will take almost anything I throw at them from the perceived "sharper" blades around - Feathers, Gillette Blacks and Yellows, Polsilvers and the like. While I can use those in the RazoRock, it's frought with a bit more peril.
I would start with a blade you know well, regardless of what it is, to build a baseline of how the razor works for you when paired with a known quantity. From there, it should be fairly easy to adjust based on what you feel and the shave you get. Good luck!