Hi jason !
thx for your replies
I do center the secondary with the ajustable sight tube from catseye. In fact I do all the steps until the autocolimator step. Then if I stack all the triangle, my secondary goes wrong (as the picture show) and it's not well centered under the focuser anymore :/

I just move the secondary in this step. If i use the cheshire in this part, i just go in circles because the autocolimator makes me move the secondary (as shown in the picture) and in the cheshire I have nothing to do except put it in the first place lol