There is a firmware sub-version in her repository for anyone who wants to be conservative with the 219B. It limits the FET channel to 50%. It is also possible to create your own firmware version with different ramp levels.
Because the red XP-E2 has a low forward voltage (and the photo red and far red even lower still), it is probably advisable to avoid FET use entirely unless you’re willing to risk killing a set.
On the other hand, the red and green XP-E2’s seem to have fairly high foward voltages and might work ok with FETs.