Sorry for the confustion, yes the second example. You create three complete policies one for each set of proxy-id. local address on the SRX the same for each and one policy for each remote subnet with the tunnel action and paired policies.
As in the example linked you have only one phase 2 policy which basically only handles the cryto settings.
The policy based vpn proxy-id are created with each policy pair in this security policy list. And you can keep creating as many as you need for the subnets involved.