I went to play fifa 10 to try this formation (4-3-2-1) and my new own custom tactics for chelsea.
Name of Player , def/att workrate :
Bosingwa , high def/med att.
Carvalho , high def/low att.
John Terry , high def/low att.
Ashley cole , high def/med att.
Essien , high def/low att.
Lampard , high def/high att.(because lampard must help defense and attack.)
Ballack , high def/high att.(because ballack must help defense and attack.)
Joe cole , low def/high att.( joe cole don't need to defense because it's enough that there is a lot defensive like lampard , ballack , essien with 4 defenders , so joe cole can give a ball to drogba to score a lot like playmaker even joe cole scored a lot.
Anelka , low def/high att.(because ........ like the same reason of joe cole.)
Drogba , low def/high att.

Custom Tactics:
Build-Up play:
speed:45 balanced (to get more possession and play very well with organised.)
passing:50 mixed (because if you want to give a ball for a far player or near player wherever you want to give , so mixed is better than short and long ball.)
positioning: organised (because if you want to play with free-form , it will be dangerous a little bit not a lot for example: ballack have a ball and run to the joe cole's place like free-form way . Then Ballack lost the ball , the player for another team took the ball behind Ballack and looked the Ballack's place is empty then run quickly because there is empty and scored a goal like messi , cristiano ronaldo and etc.
Chance Creation:
passing:65 normal(to create a chance in the penalty area.)
crossing:60 normal (when midfielders arriving in the box)
shooting:70 lots (because you want to shot a ball anywhere.)
positioning: free-form (to create a chance anywhere or shot or cross.)
Defence:
pressure:30 deep (because deep pressure makes another team difficult and keep away from against's score.
aggression: 40 press (because 40 press can contain and tackle hard whatever you want so it's better.)
team width: 45 normal (because 45 normal makes another team difficult.)
back-line: cover (because if you want to use offside-trap , it will be dangerous when the trap is broken , the another team will score easily , so cover is a safe defense and cover is better than offside-trap.)

The result of this formation and custom tactics for chelsea in online:
chelsea 5 - 0 chelsea
chelsea 3 - 0 arsenal
chelsea 4 - 1 barcelona
chelsea 4 - 3 manchester united
chelsea 6 - 1 roma
chelsea 3 - 1 liverpool
chelsea 2 - 0 france
chelsea 6 - 2 barcelona
chelsea 4 - 1 real madrid

how is my opinion? tell me everybody come on.