I only append -o ro option if I want to mount a drive in read only. else, just use the mount command followed by the device path and mount point after that. By default naman kasi if you use mount without any appends by default read/write mode agad yan.
As for persmissions, -o rw append is not a a permission, more like a mount option. Kung gusto mo lahat meron read/write access dyan sa drive na yan. you might wanna use chmod 777 instead.
PH