I am trying to install DS' new Como and I am struggling to get the angle right. I have tried a towel and a pool noodle but I can't get the base level (which is what the manual says). DS is 3m, is it critical that the back be at a 45 degree angle? If so, can I use 2 noodles or a noodle and a towel? Or is this a case of this seat doesn't fit this car ('04 Toyota Sienna)?