Try to place codegates at front and after that arrange scanner....
this will slow down the intruder lil bit also your sentry will get some time to spread the antivirus in network &
Try to place core @ the end or corner where you have placed the guardians...
Or place databases and mines after the core then arrange them in low level node(choke)...
Dont hack networks if you dont need money or you already have enough $ and B-coins bcoz this will
attract more attackers...
I dont have level 9 core but i am currently upgrading to core 9...below is my network you can also arrange like this, well this is effective for me...
