Marginalised 1σ errors on cosmological parameters relative to their corresponding fiducial value for the pessimistic baseline case, which equals to |f_R0| = 5 × 10⁻⁶. We show results for GC_sp (purple); WL (blue); GC_sp + WL (orange); the combination of all photometric probes, including cross correlations, WL + GC_ph + XC_ph (red); and the combination of all spectroscopic and photometric probes, GC_sp + WL + GC_ph + XC_ph, (yellow). One can see that the constraints on log₁₀|f_R0| and σ₈ are similar among GC_sp and WL, but for other parameters such as the Hubble parameter, h, or the fraction of baryons, Ω_b, 0, the constraints coming from GC_sp alone are even more stringent than the constraints of all photometric probes combined on their own.