Mail Gateway configuratiom and permissions issue

[themrkys]

We have 3 servers at the moment.
Server 1 is ISPCOnfig Nginix, Mysql
Server 2 is NGinix, MYSQL
Server 3 is MYSQL (maybe did not need this) and postfix

I want server 1 and server 2 to relay using server 3, I made the addition of a mynetworks has file which worked fine. I just updated to the latest version and found two big issues,
one the mynetworks change was reverted causing all mail to be rejected until I realized and fixed the problem
two permissions to the mail_* and spam_* were undone such that the user created for server 3 did not have select access. I was able to correct this manually but it appears that this is a bug ispcsrv3

Side note do I need mysql on server 3 for any reason can I remove it?

Is there a way to retain the configuration?

Additionally a service I provide is to allow customers with their own on site exchange servers to relay through my mail servers to avoid penalties associated with broadband networks. What is the best way to manage that configuration using ISPConfig?