When I had my 4 spokes diamond cut they wouldn't laquer them as they were 'old' lol and it would go manky.
They were left bare alloy and was told I would have to clean them everyday. The novalty of that wore off after about a week and after a year they needed refurbing again.
Although car was used daily in all weathers..
It will hold the rust back for a while but thats it.
Best to wire wheel and when you think it looks rust free, then use the kurust as there will still be tiny rusty pits that are hard to see and the wire wheel doesn't get.