Likelihood ratio of 6000 sky maps modelled with PSYCO relative to the likelihood of a background-only fit with the SPI. Dots and solid lines denote the average values from 100 MC runs as a function of scale height. The colours correspond to stellar model configuration as noted in the legend. Triangles mark the maximum TS value obtained from the 100 MC samples for each model configuration. The thick grey lines denote the reference value obtained with COMPTEL (TS = 2160) and SPI (TS = 2166).