Change from One ARM to DGW mode

Our deployment now is one Arm by using SNAT AutoMAP , the VS and Pool members on the same subnet but the clients are in different subnet ... We have only one Self IP in the same subnet of Pool members

 

We need to change this deployment to be F5 as DGW for backend servers ... What is the exactly needed to deploy that ? Should configure the VS on different subnet? Should I configure Forwarding IP VS with Source IP any and Destination IP any on all VLANS ? should I configure another VLAN with other Self IP (External to clients)?

 

And if there are admins should access directly the backend server, should i change FW rules to allow access to self IP ?