How can I schedule a Google Calendar event for recurring twice-monthly payday?

How can I schedule a Google Calendar event for recurring twice-monthly payday, which recurs monthly on day 15 or the last day of the month OR if either is on a weekend then the prior weekday?

I assume I'll need to manually create an iCal file externally then import it into Google Calendar via Settings ► Calendars ► Import Calendar.

Ideally it would somehow also know about US federal holidays and consider those to be like a weekend day, but I'll accept an answer that ignores this complicated requirement.

_{P.S. I've seen similar questions like How to make a task repeat on the last day of each month in Google Calendar? but never one just like mine.}