Multi tenancy | Merchant specific theme app extension | How to avoid per merchant custom app hosting

[raghav_kanwal]

We have built a custom app (public app is not an option) with has merchant/shopify store-specific theme app extension. We will be using Heroku for hosting our custom app. In order to avoid per-merchant hosting, Is any of the following architecture models feasible:

1) single theme app extension but has mappings/app blocks per merchant and can be dynamically rendered based on merchant store?

2) separate per merchant/shopify store theme app extension mapped to a single/shared hosting of app over heroku?

Please suggest, thanks