I skimmed through this and when it comes to the welfare of the animals I want you to consider hypo,tank transfer is a quicker cheaper method but IMO harder on the fish.Don't bother with copper,too hard to moniter/dose and can be worse for the fish.
Set-up a QT,sump it,skimmer heater etc throw in some rock and run it at 1.010 sg. for at least the amount of time you main needs to be fallow,longer the better...8-10 weeks should do it? lower sg makes life easier for the fish so longer won't hurt!!
I have tried both and I didn't carry out the transfer method properly but moving the fish every three days and dealing with the water quality in a small container was a pain.I lost three fish and ich became worse so into the frag tank they went and down came the sg.Fish were on the edge for a few days but are fully recovered now,I think the TTM would be great for one fish!
I had a severe case and within 4 days in hypo it was 60% gone,that was a month ago and a relief! Hypo will kill off everything,snails,shrimps,sponges,feather dusters etc but I think beneficial bacteria survives,I still need to find more exact info. on this!
I know hearing someone tell you to go spend more money on another tank is not ideal but you'll always have it as an option and you can pick up stuff pretty cheap in the buy/sell forums.
I shut down my big tank and considering a restart and if so I plan to start up in hyposalinity and try to stock my complete fish list,run it for a cpl months before bring the sg back up and goin ahead with corals etc. Still some reading to do for myself on this approach.