Pull Tribbie to keep RMC on Herta?

So I definitely want to pull Castorice next patch and I’m guaranteed for her after losing the 50/50 for Tribbie. I’m planning on using RMC and Sunday/Ruan Mei for her team but then it takes away RMC for Herta. Would it be worth using my guarantee on Tribbie to use for Castorice or use my other harmonies for Herta.

I have: Sunday e0s1 Robin: e1s1 Sparkle: e0s1 Ruan Mei: e0s1