There are several consideration.
(1) Organizations: make sure you know how many organizations participating in your application. Usually it means the different companies, plus some governance bodies, audit, etc.
(2) Then you may need to know how many nodes and what functions needed, based on the actual business case. The minimum peer resource for each organization shall be two for HA, but more means more capacity when needed.
Therefore, First Network is a good model to follow. You can extend it according to your need.
(3) Finally, to make it production grade is more than an architecture. You have to consider where to deploy and the day-2 operation on the network. You need a team to maintain such a platform, or outsource to other companies. As it involves cross-company, a very detail planning and design is critical for a production-grade blockchain platform.
Just some rough ideas. You can reach me on firstname.lastname@example.org for further discussion.