Self IP in different subnet and VS and pool members are in same subnet then Self ip

In my view, following should work -

Option#1

• You would have to cut the new network for VIP from 10.10.10.0/24. ( e.g.10.10.10.64/27) and it should be dedicated to the F5 VIPs only. so on the network you can have a route to reach VIP network 10.10.10.64/27 pointing to floating selfIP on F5 (lets assume 10.10.20.2)
• Since F5 has only 1 leg in 10.10.20.X (lets assume 10.10.20.1/25) , default gateway on F5 should be in that subnet. Default gateway of F5 should have routing to the server network or should be directly connected network to the server farm.
• You would have to use SNAT on F5. So all source traffic from F5 to the server will originate from selfIP (lets assume 10.10.20.2 is floating selfIP). Sever's gateway should have route to reach F5 network (e.g 10.10.20.1/25) pointing to floating selfIP 10.10.20.2.
• There is no need of return route from F5 to the client as auto last hop feature would take care of it.

Option#2:

• Since you have SelfIP network (lets assume 10.10.20.1/25). you can host VIPs in this network and network would have route to reach this subnet pointing the floating selfIP.
• All other settings would be same as above.

 I would suggest to go with option#2 as a recommended way of having selfIP in the VIP network