@TomD8,
Thank you for pointing me to that reference. From there I followed it to:
MA Gross, Adjusted Gross, and Taxable Income for Nonresidents | Mass.gov
According to this reference, activities such as training, conferences and management reporting are considered "ancillary activities" and do not count as conducting business in MA. Therefore, apportioning the MA sourced income by hours or days should not be necessary and I believe the MA wages can be set to $0 as you and @MayaD have described.
