This should help:
Alternatively you could weigh a completed print and use the Preform-estimated resin volume to get a ratio to use for future estimates. If you print direct-on-base that would exclude the volume consumed by supports.
If you’re really keen you could print in Open Mode or with an empty cartridge installed, and measure the volume change yourself (or use before/after tank weights to calculate it). A holder like this could help you drip off as much resin as possible before removing the print.