I'm not highly qualified to answer, but its nearing 24hrs with no response.
My answer is yes, you want to be below 10nm, especially with Oiii. Some people go 5 or 6nm for Ha and Sii, and 3nm for Oiii. Oiii seems to be most impacted by moonglow. I use zwo 7nm across the three and definitely notice the extra noise with Oiii. I wonder about getting 3nm version for that one in particular. But yeah 5 or 6nm are the standard, it seems. I went 7nm zwo for cost reasons