An update for anyone interested: according to the folks at Avient, the 2 substitute inks for Union EF Athletic White are Zodiac Libra RFU White (no Nylobond/Hugger Catalyst needed) and Epic Topscore LC White (will require Nylobond/Hugger Catalyst to adhere to the garment). We just got in some Topscore LC White to our shop, so I'll report back after we've tested things out on press.