Sorry for the slight delay in my reply;
So at the moment, my setup is an Airport Extreme configured in IPV6 tunnel mode as per the config settings I got when I generated my tunnel.
The devices just seem to connect and get a random address within my allocated /64.
Something's telling me that the Airport Extreme is not providing specific addresses (as I understand it, IPV6 devices can do addressing themselves and don't necessarily need DHCP?) Being an apple product, the UI is nice and simplistic, but lacks anything other than an 'IPV6 MODE' and relevant tunnel settings which you can configure.
Do you think that i'm just needing a DHCPv6 server like a raspberry pi on my LAN to do specific address delegation?