upgrading kali on pendrive. no space left

Hello everybody,
i was trying to make a bootable usb pendrive following these tutorials:

http://docs.kali.org/downloading/kal...ve-usb-install
http://docs.kali.org/downloading/kal...sb-persistence

i was able to make a bootable usb pendrive with an encrypted persistence.

However when i tried to upgrade the os the space left on the usb was almost 0.

i tried to change the space for make the persistence partition of kali with these values:
NB: my pendrive is 32 gb

1) start what indicated on the tutorial
end: 31gb

2) start 16gb
end 31gb

3) start: 24gb
end : 31 gb

sadly all the time after the sudo apt-get upgrade the same problem occurred.