Third-party analytics indexing on Canton: public Scan vs private party-scoped read path

We’re Top Ledger (https://topledger.xyz/) — and we’re evaluating how to index data on Canton Network.

We’ve gone through the Canton technical and onboarding docs (ledger/ACS model, Scan, Ledger API, PQS, validator topology). From that, we’re seeing two potential paths:

1) Public / network (Scan / DSO-visible)
Canton Coin (supply, mint/burn, transfers, fees, mining rounds), validator/SV activity, CNS, traffic, governance, and network health.

→ Closest to what we do publicly on Solana today.

2) Private / app-scoped (party visibility on a validator)
Positions, holdings, settlements, ops metrics, audit trails — only what the customer’s parties can see.

→ This looks like the institutional product (tokenization / stablecoin / settlement apps), delivered as managed indexing → SQL/APIs/dashboards, similar to our private Solana customers — but clearly privacy-scoped.

We’re looking for clarity on (2) in particular:

1. For app teams / institutions, what’s the supported / recommended way for a third-party analytics partner to get a read path — Ledger API (party-filtered), PQS, in-VPC indexer, observer party, or something else?

2. How common is it in practice for customers to allow an external indexer?

3. What’s the realistic onboarding sequence (parties, JWT scopes, DAR/templates, traffic, environments)?

4. Any reference patterns or constraints we should look into first before doing any indexing?

Would appreciate pointers from anyone who’s done this or if you’ve seen this pattern in practice. Thanks.