So, first off, the error I had was that when I made these all the first time, instead of having the even spacing of 25 CI between each variant, I accidently made the ones that were meant to be ending in ‘85’ (185 CI, 285 CI, 385 CI) 10 CI larger. So there was a 35 CI jump from the X60 CI displacement and only a 15 CI difference to the x10 CI ones. Hopefully that explains it well enough.
As for the sorting, in the default sorting it seems to go by order of creation from the newest to the oldest. So I would create a new variant, close and open the engine designer back up and the clone would be above the original.
And the detuning of them is mainly to have them all be there, and if I made a car to use them in future I can either use whichever one I need to and retune it or make a clone to use depending if I use it in multiple cars.
You’re welcome to share your engines if you wish, these are all remade from my ‘official’ brand really: Ascot Automotive