How do I correctly configure stock settings?

Another question...

What's the correct configuration to do the following;

1. When someones purchase the last qty of a product, it shows 'Out Of Stock' but still shows on the site?
2. No backorders are possible - ie, customers can't order 'Out Of Stock' products.
3. Customers can choose to be updated when a product of their choice comes back into stock - ie, when the admin increase the qty to above '0'. However, I only want them to subscribe to 'Out Of Stock' items.
4. The admin receives an email to notify them when a product hits '0', or possibly '1'.

I think I have some of the above configured correctly, but just want to make sure.

Cheers all!

1 and 2 - Configuration --> Stock
4 - Configuration --> Stock (for levels) and Configuration --> Email Options (to send the mail and address to send it to)

As for 3, not sure. They can manually subscribe via the current product notifications feature, but don't know if there's a mod to do exactly what you want.

HTH,