I’ve been approached by an ex-WL to sponsor her for PR under a subclass 820 Partner visa.

Does anyone have any experience they could share with:

1. Market price for how much the girl should pay for sponsorship
2. Timing of payment instalments and milestones
3. Methods to protect your own assets eg pre-nup
4. Whether you went down marriage or registration of de facto or proved 12 months of cohabitation

Pms are welcome if sharing sensitive info

Cheers gents