Did the Senegalese used the Bleu Horizon uniforms at some point in the Great War? I always thought that they used Dark Blue uniforms in the beginning then switch to a Moutarde uniforms (kind of brown/yellow mix) in 1916? 
Yes, in France they were initially clothed in their dark blue uniforms, then switched to Horizon Blue for a time when it was introduced in 1915. When they went to Gallipoli they apparently (according to Osprey) reverted to their sand-coloured African tropical get-up, but with the addition of blue puttees. Then as you say, in 1916 they changed to the new mustard-coloured uniforms.
I'd love to see some figures in the tropical sand-coloured uniforms (collarless jacket and calf-length trousers, no puttees, barefoot or in sandals) so you could use them to fight the Boche in Africa. But Hell, it's great to see any kind of Tirailleurs Sénégalais, and I am thankful they are available, so I shall not be churlish enough to mention it again.
