Should I clean my sysNAND and put it on 8.1 or keep it on 7.0 fuses?

How do you exactly intend to "clean" your sysnand.
Unless you've made a backup prior to doing hackery stuff with your switch there's no other reliable way of properly wiping traces of homebrew/hacking from your console.
There this guide about doing so by using hacdiskmount and deleting some save data off your system but I'm highly skeptical on that.
Anyway. I would suggest you to set up emuMMC and keep your sysNAND on 7.0.1 whilst updating your emuNAND to your latest version for games and such.
Refer to this guide for any further inquires regarding emuNAND.
Note that in order to prevent the fuses from blowing autoRCM must be kept on at all times.

 

There is no point in keeping 7.0 fuses if you have access to jig+dongle.

 

I'm running 8.1 OFW Stock thru Hekate alongside an 8.1 CFW EmuMMC with only 6 fuses burnt and I haven't been banned. If you need online play thru OFW I'd recommend using the same method and preserving your fusecount for a future downgrade.