What is your defensive plan? Are your WB's sitting high up the pitch or do you have a Def/Support option set for them?
Seeing as the Cb's are stretched, there is too much space to effectively play an offside trap so go with stopper/cover.
against teams who like to
play wide, I'd opt for a
LWB(s)----------------RWB(s)
CB(s)--CB(c)--CB(s)
View attachment 401147
The LWB/RWB are set to cover the runs of aggressive full backs and prevent passes into deep lying forwards or onrushing midfielders. The two outside CB's are set to stopper so they will go engage and harass the opposition (1) wingers and not give them much time on the ball while (2) the inside CB is set to Cover to drop and defend the middle channel from wingers cutting inside or thru-balls to a striker/AMC running in from deep.
Against teams who play
through the middle
LWB(a)----------------RWB(a)
CB(c)--CB(s)--CB(c)
View attachment 401150
Becasue there is not much of a wide threat, you can leave your WB's on attack to stop deep runs from the opposition FBs. The central CB is set to stopper (1) to put pressure on the Striker and stop him to cleanly receiving and playing the ball. The two wide CB's have cover (2) assigned to them as they track back and defend against knock ons and thru balls played by the striker towards onrushing midfielders or inside forwards.
If they are playing with WB's, be sure to man mark them with your own wing backs to put pressure on them as you wide CB's (3) will also close them down forcing a 2-on-1 situation to regain possession.
This is just really off the top of my head so I'm not sure how tactically sound it is. You may need to tweek the player roles to get it to be truely effective with you players but 3 at the back is a system i love myself and have experimented with a lot in the past.