Dhenry
Do not fully understand what you mean with Offline calculation of the mapping.
PeterH
This whole slotrace controller project is not standard so we try the things step by step.
Currently all controllers that have an exponential curve just run from the startspeed point to full speed.
For those just stepping in and try to help.
With the selectable XY switchpoint we try to be different and this has not been tried or tested before.
Now for this step in the project we like only to curve the last straight line by changing a curve value.
1 is a straight line and 3 a full curve.
We have to test if good slot race drivers can benefit from this last line to be linear or to be curved.
Also even if the lines are linear we not yet tested with drivers if this would be enough and the curving is not needed at all.
But I like to have it already and then test drive all possible options at one day to have comprehensive comparising with same drives and track conditions.
All settings to XY and curve value need to be changeable while the controller is plugged in and in use.
This is where the project currently stands and we are not ready yet.
I am eager to learn but my level of programming and mathematics in not at the same level you guys are. 
Your given options are acabadabra to me so I cant say if this or that would be better or give an other result that is desired.
Cheers, Paco