Replying to FIT: Kaos vs. Rampage

Okay so i already know that the Kaos is a wider boot than the rampage but im just wondering in terms of length. If i were to get a 27.5 in both boots would the length of the boot change because of the brand? I have 27.5 rampages now and they fit me perfect besides the fact that they really hurt my ankle bones and i didnt want to get boot work done in that area so i just sold em and i am unable to try on the kaos. i know from searching that the kaos have more volume fit compared to the rampage. so basically what im asking is what are the differences in fit between the two boots besides the more volume in the kaos than the rampage. thanks!!