Help with Loyalty Counters

Hello, I have a fully built Super Friends deck that I've made alter sleeves for, turning them into Marvel characters! I need some help though, with the new Phyrexia All Will Be One set out, I want to put Ichormoon Gauntlet into the deck but am unable to put the -12 Loyalty ability into the ability box. It appears I cannot put a two number value to the icon. Any idea how I can do this? Attached is the card I'm altering, along with some of my previous successful alters