W-8 and W-9 as it pertains to NRA Payroll taxation

We currently manage our Nonresident Aliens payroll taxes quite manually, having to go into paylines and balance tables to adjust some of the taxation and taxable gross. While we do use 1042-S configuration, Presence Tests, and Tax Treaty enrollment on the W-2 page, we do not use the W-8 and W-9 fields on the employees' W-2 tax setup page.

We want to use these fields in the hopes it reduces our manual intervention, but we do not have an understanding on if/how entering W-8 and W-9 information will change NRA taxation. Apparently this was explored years ago but didn't work as was expected so we switched to making manual changes. We're not sure if we are missing a key configuration or not; but we do have other configurations setup (such as adding 1042-S codes to Earnings Codes)