I had noticed this deliberate lower FG when I was doing Toyota 86 TT where @
eclipsee's gear ratio setup where instead of setting FG to usual max value, for that case it was 5.500 I believe, his instruction was that you set it at 4.300 of something like that. The theoretical top speed would be the same with any given method as long as you get all the gears identical but I knew there was more to it than that something those aliens aren't telling.lol
There we go then ...
I almost always use this kind of gearbox, this gives you good acceleration and the car rotates slightly better when turning, it's the main reason why I was 2 km/h faster at the starting line than others in the MX5 seasonal TT.
In short words, it's simply the transmission trick but the final gear set always at the minimum value.
Procedure:
1.- Use the default gearbox settings and find what's the max speed at the final of the longest straight of the track.
2.- Tweak the top speed slider in order to match the top speed you found, this step is only to find a reference point for the 6th gear (or whatever longest gear has the car)
3.- Draw a vertical imaginary line from the point where the 6th gear line ends to the letters above, take note of that letter, this will be the reference point when later you'll adjust the final gear to the minimum value.
4.- Now begins the tedious trial-error step in order to find the origin of the final gear, set the final gear in the middle, let's say at 4000 for example, top speed minimum, 6th gear slider all to the right, final gear minimum.
Does the 6th gear match with the reference point you've found?
Yes -> then 1rst and 2nd gear slider all to the left, don't touch the 3rd, 5th and 6th gear all to the right, set the 4rth gear in order to make an imaginary diagonal line from 3rd to 6th gear.
No -> Try a higher or lower final gear value and reset the top speed (one click to the right and one click to the left) , repeat step #4 until the 6th gear matches the reference point you've found, remember that the slider of the 6th gear must be all to the right and the final gear must be all to the left when you finish.