The Boss Katana Tone Studio utility has a very good noise suppression setting. I read a lot of reviews that mention the Katana is very buzzy, but the noise suppression takes care of it. It definitely made a big difference on mine. I have the 50 Mk ii. It is a little annoying that this requires you to tweak the settings using the software. Here is a video showing the difference with and without the noise suppression setting.
It takes as long as it takes unless you quit - then it takes forever and you will never get there.
