I measured the oil amount in my forks when I disassembled them to install the AK-20 cartridge kits.
The oil amount was 475cc. I didn't measure the oil level at the time.
The oil level recommended by Traxxion-Dynamics with their AK-20 cartridge kit was 120mm without spring installed.
Both T-D and Kyle Racing do not use the oil lock piece, relying on oil level to control maximum fork travel under full compression.
The OEM quantity of oil recommended is 498cc.
On a related note, I also rebuilt my Ohlins forks, and without springs, 120mm of oil level is equal to 93mm with spring installed.
While different forks, the springs in the Ohlins forks are virtually the same free length and possibly diameter as the springs from Kyle Racing installed in my OEM forks, and may displace the same amount oil.
So you may use this as a rough estimate.