I was under the impression that HPPD is probably related to an uninhibition of COMT and maybe not normal neuronal damage, but I don't know why COMT begins to have problems. Antioxidants are a good thing Royale anyways during trips but idk, I would guess that the risk for HPPD is still there.
Now that being said, in my opinion that biggest risk factor for HPPD from any drug use is missing sleep - make sure that you get as much sleep as you can by dosing as early as you can. Chronic sleep deprivation causes HPPD like symptoms as well. If you find yourself having sleep troubles it would be worth it to find something with 5HT2A antagonistic properties to take at the tail end of a trip.