Change cars in progress championship

After some time without touching the CSM, and remembering very little, I ask:
What is the best way to change shape (and textures) as a 17-race championship progresses?

I have shapes and skins from the 2014, 2015 and 2016 WEC seasons,
I want to use the 2014 set in the first 6 races. From the race 7 to the 12 the set 2015. And from the race 13 to the 17 the set 2016.

I've done it that way (works perfectly but is it possible to do better?):

[Main]
Format=
[Config]
SkipBuild =

Dir1 =Toyota 2014
Dir2 =Nissan 2014
Dir3 =Audi 2014
Dir4 =Peugeot
Dir5 =Porsche 2014
Dir6 =Bentley 2014
Dir7 =Ligier 2014
Dir8 =Rebellion 2014
Dir9 =Mazda
Dir10 =Lola 2014
Dir11 =Lotus 2014

Dir12 =Shared 2014


[TrackSpec 7-12] (same configuration for each track from 7 to 12)
TargetFile =Season-2015
DisableCopy =
Dir1 =Toyota 2015
Dir2 =Nissan 2015
Dir3 =Audi 2015
Dir4 =Peugeot
Dir5 =Porsche 2015
Dir6 =Bentley 2015
Dir7 =Ligier 2015
Dir8 =Rebellion 2015
Dir9 =Mazda
Dir10 =Lola 2015
Dir11 =Lotus 2015

Dir12 =Shared 2015


[TrackSpec 13-17] (same configuration for each track from 13 to 17)
TargetFile =Season-2016
DisableCopy =
Dir1 =Toyota 2016
Dir2 =Nissan 2016
Dir3 =Audi 2016
Dir4 =Peugeot
Dir5 =Porsche 2016
Dir6 =Bentley 2016
Dir7 =Ligier 2016
Dir8 =Rebellion 2016
Dir9 =Mazda
Dir10 =Lola 2016
Dir11 =Lotus 2016

Dir12 =Shared 2016

Thanks in advance

Mods & Tracks for GP4 - [www.mediafire.com]

Keeping alive the GP4

Try asking phantaman...he's great with this sort of thing...