Job Manager: automate / schedule patching

[infecticide]

We have a Xenserver 8 environment and the only reasonable way to do patching currently is to use XenCenter. We have a large environment with a large number of VMs and hosts. Patching can sometimes take more than 8 hours.

Our company works with Citrix Virtual Apps and Desktops, as a result the session must be kept active so XenCenter isn't killed and leaves the patching in a broken state. It would be nice to:

A) Not rely on Xencenter
B) Have patching scheduled to begin at a certain time, like 4 or 5AM. Then the technician can login and out of XOA throughout the day to check on it and leave without worrying about the process stopping because XenCenter closed.

The Job Manager seems to be limited to host and vm power actions. Could it be extended to automate patching?

Looks like all the relevant steps are laid out here:
https://docs.xenserver.com/en-us/xenserver/8/update/apply-updates-using-xs

I would like to be able to setup a job to begin patching a pool at a certain time and date. Maybe with a pivot on one-time vs repeat on a schedule.

I had considered writing some powershell to do it instead but having the experts put it into XOA would be better than my scratch ;-)