Example binning solutions. Left: Initial binning solution for the galaxy cluster RXJ0856.1+3756 (solid white steps) from the algorithm specified in Sect. 4.3. The solid green curve delineates a 30σ S/N requirement. It shows that indefinitely adding more input S_X bins to an output kT bin is suboptimal. The cyan steps represent ${\stackrel{\sim }{b}}_{\mathrm{in}}$, corresponding to the optimal innermost S_X bin to include per kT bin, described in the galaxy-cluster specific amendment in Sect. 4.3.2. Right: Same but with the galaxy-cluster specific amendment applied. Here, the S/N landscape is capped (1) globally to the S/N value at the rightmost b_in above 30σ for each b_out, and (2) at $b_{\mathrm{in}}<{\stackrel{\sim }{b}}_{\mathrm{in}}$ to the S/N value at ${\stackrel{\sim }{b}}_{\mathrm{in}}$ for each b_out. The colour scheme has been adjusted so that the effect of the S/N landscape capping procedure is visible.