Cool thanks,
If I understand correctly the heat map of the optimal layout proposed by the website algorithm, the priority is this :
left hand before right hand, alternating
home middle finger
home index
home ring finger
home centered index
home little finger
up index
up middle finger
up ring finger
down index (down centered index on right side, then down right index)
the rest kind of beats any pattern... I'll have to look at it more in detail.