tbh i think a nice lazy way to qt would be:
h2o2 bath, put fish in a 10g tank. dose GC/prazi. let simmer for 3 days
swap fish out into a different tank. let simmer for 2-3 days, dose GC again 24 hours prior to moving the fish. then h2o2 bath en route to your DT
this won't eliminate ich, but it...