No split tuning on the GFI unfortunatley

.
All is not lost however, it's just a bit of a tricky balancing act if you want to do it without additional hardware.
I've just carried out this change on mine & had to change the bell crank hole on the 10 string in my case in order to increase the feel when the 2nd got to D & then mess with the amount of travel to bring things back in line.
It will be easier on a standard ten string 'cos you
lower the 9th & it should be possible to improve the "feel stop" by increasing the lower spring tension ( I don't have that luxury, since I'm actually raising to D on the lower 10th String)
Either way it's still a PITA untill you put in the seat time and get used to the feel (it's so so easy to over lower in the heat of the moment)
Hope this helps