I’m working on a similar task at the moment.
HID Iclass proxmark3 - Support - Dangerous Things Forum
Not to hijack your thread, but this may answer some questions or maybe give some insight I hope. I’m by NO means an expert, but if I can help at all, ask away!
You should be able to
hf ic rdbl -b 6 --ki 0
or blocks 6-9, changing -b 6 to -b 7 etc.
noting that value, and then with the blank card on the pm3
hf ic wrbl -b 6 -d “value for each block” --ki 0
if you’re using the redteamtools Iclass card like I am, if --ki 0 doesn’t work, --ki 2 worked for me
Or, at least that’s my understanding of it. There is a lot of knowledge floating around here. I try to absorb as much as I can!
I hope it goes smoother for you than it is for me so far! 
EDIT: @philidelphiaChickens gave me some wisdom about using the key from managekeys instead of typing the key out manually to avoid any potential uh oh’s