Dependence of weak lensing cluster masses on the choice of centre and mass-concentration-relation. Upward and downward triangles show the masses using the B01 and B12 mass-concentration-relation relative to the case of a free c₂₀₀. The square and small triangles present models centred on the S-peaks for the free-c₂₀₀, B01, and B12 cases, respectively. Clusters are ordered by increasing (free) c₂₀₀ in the S-centred model. Grey lines denote the statistical error bars in the reference model (ROSAT-centred, free c₂₀₀).