Salomon Ghost 120 vs NEW 2015 Ghost FS 90

I tried on a pair of Ghost FS 90 and they felt great but I am a little worried about the flex, I know I can put another bolt in the back to stiffen them up. I am wondering how the sizing is between these 2 boots since you can heat the Ghost 120 to make the last wider. I am guessing the heal might be a little tighter on the ghost 120 since it's a 98 last but I don't know how much tighter since there is a pair I am looking at I can't try on. The new Ghost FS 90 felt great,maybe a little loose in the heal but good overall. Are the sizing on these boots comparable or did they change the models a lot in the last year? Also I noticed they don't do the custom shell anymore, is there a reason?