By the end of the 2004 storyline, it was pretty clear that Vakama could only forge the Mask Of Time from the Great Disks. Since the Great Disks are still Kanoka, they can be forged into a Kanohi mask just like any other Kanoka can.
But perhaps the Great Disks couldn’t all combine into one OP disk, and instead into several different disks and then be used to create masks. Like, use three disks to make one mask, and use the remaining three to make a second. Canonically, their powers are Enlarge, Regenerate, Freeze, Weaken, Teleport, and Reconstitute At Random. Going off the combination chart that BioSector01 provides, here are the possible masks that could be made from the Great Disks:
Hau
Miru
Kakama
Akaku
Mahiki
Ruru
Kiril
Kualsi
Mask Of Growth
Whatever the Great Disks would’ve been used to make, one thing is certain: the resulting mask would put almost any other mask to shame.
But I have updated my view on the mask Nuhrii wanted to forge, since I made that topic.
In the 2004 story bible, it is specifically stated that the Mask he wanted to make out of the Ta-Metru Great Disk was a Pakari.
This means He would have had to include two disks of power level 8: Regeneration and Remove Poison. That would make the resulting mask only 1/3 legendary Pakari.
If he somehow got his hands on the Ga-Metru Great Disk (Regeneration), it would be 2/3 legendary Kanohi.
I wonder what power level would that make? We do not have any information on what happens if you forge a mask from Kanoka of unequal levels of power.
My personal explanation would be that if you mix disks of different power levels, the inferior disk can’t handle the level of power that the other disk is sharing with it, and the protodermis disintegrates or something.