Sorry I'm late to the party. I usually skip this forum for a variety of reasons but since I was asked I'll go into a few things.
The 0.05% salt solution works out to about 1/2 tablespoon per five gallons of water. That should also translate into about 1 and 1/2 teaspoons per five gallons.
Goldfish have no problem with salt addition at all and I've taken them as high as 3 tablespoons per five gallons. The main thing for countering ick is making sure you meet the minnimum requirement.
I wouldn't rush to get the salt back out. It's not going to hurt anything having it in there and you might want to carry the dosage through to the new tank for the first month or so until everything settles down.
Ick reinfests the gills heavily and goldfish are high oxygen needing coldwater fish. Cranking the temperature up too high lowering the oxygen levels in the warmer water at a time the gills are infested with baby icklings making breathing difficult could be a bit risky. I would probably stay at 75 myself and work on relieving the stress that's triggered the outbreak and any secondary issues that come up from fin rot to infections of the exist wounds where the ick left the fish. If you can locate a store selling Jungle brand meds in crystalline form I've used Fungus Eliminater by package instructions in addition to the salt to treat goldfish more times than I could put a number on without a bookkeepers help.
http://www.junglelabs.com/pages/details.asp?item=NJ117
A secondary concern I hope you don't have to deal with is some weird internal problem that seems to be running through the goldfish this year. I've managed to lose five out of my first seven goldfish this year to the exact same symptoms, two red cap orandas, two black moors and a calico oranda. The symptoms come across as one day the fish is sitting on the bottom not moving. You go to the tank and it gets up and swims around normally and eats great. The next day it's dead. No time to react or treat in four out of five cases. I'm trying another black moor and red cap right now. This problem has been appearing about 3 weeks after purchase. One week in quarantine has passed without incident on the two new ones. If I lose anymore I'm going to go back to prophalictically treating with salt and Fungus Eliminater on the next attempt.