Actually, since this is for Auto VPN only, there is no need to define destination addresses.
You only do source NAT, the other end do its own source nat and those subnets should be advertised in the routing table.
192.168.1.1/24 -> translate to 10.0.1.0/24 -> talk to -> 10.0.2.0/24 <- translate to 192.168.1.1/24
If you want to have 1:Many source nat, the Port forwarding and NAT might be an option, but I doubt they will source traffic from s2s vpn interface. They are designed by default to source traffic from WAN interfaces.
Therefore, this is is more like to work when you have multiple sites with same IP range connected to a VPN HUB which will only initiate communication with the networks behind HUB but not between them, or networks behind hub will not be able to initiate communication with them.