Here are the steps I am using. Is this the correct/best way to accomplish? And is there a risk of patched and original files becoming out of sync?

Uninstall patches
Apply Community Builder 1.8.1 to master through Joomla Update
Reinstall patches
Go to slave site and install CB 1.8.1 to get DB changes
Go back to master and reapply the CB patches that got overwritten
Do this for each slave site

I had some issues, but I was doing a whole series of updates including a Joomla update that changed the DB. Did it in phases, but at the moment I cannot confirm which step killed my master so don't have specific question about that yet. I restored from BU and am fine. Retesting in test area, but would like some clarification here as well.

The directions discuss DB change propagation, which I have not had any real issues with, but this affects the patches when I run the upgrade on the slave site.

Thanks,

When updating something in your environment, we always recommend that you make a backup before changing anything.

After that, when you update/upgrade joomla, it is recommended that you verify that you have the latest JMS installed. Sometimes (not frequently), we have to publish a new JMS to be compatible with a new Joomla version.

When you update Joomla this may result is removing some patches. In despite the fact that we are trying to make the patch ineffective when something is missing, it may happen that it cause fatal error when partial patches are installed.
This is the reason why we recommend to uninstall the patches before updating your joomla. The disadvantage to uninstall the patches is that all your slave sites are using the master instead of their content (as JMS is inactive).
Therefore, when it is possible and if you have a test environemnt, you can trying updating joomla without removing the JMS patches.
It is possible that have a "DB error" because a patch is not installed. As you have direct access to the "Multi Sites" submenus, you can go directly in the "check for patches" and re-apply the patches.

Concerning the update/upgrade of extension, this is extension dependent dans depend of their version. Personnally, I always verify in a test environment all the update/upgrade before applying them in production.

Makes sense, and thanks. It does clear up a bit. I do use a test area, stays in sync with production, I do everything there first then replicate steps, once I've confirmed they worked, in production.

When I apply the CB 1.8.1 upgrade in a slave site it overwrites the patch files. Is there a chance that when I reapply the patches in the master the "clean" original files get out of sync?

I'm going to try uninstalling the rest of the patches first then reapplying them.

What I was getting was a blank screen, PHP error after the CB update, but not necessarily right away. at first it appeared to work.

I'll attempt to replicate, but working on deadline at moment.

Thanks

When JMS apply a patch, it reads the existing sources.
So if a patch is required on Community Builder, it will be applied on the current source installed (here 1.8.1).

In general, for the extension update/upgrade, it is not required to uninstall all the patches. So you can just return in the master and apply the patches to fix the extension patches.