I used this tactic from the beginning of my save and it has been working really well for me, gaining quick promotions from the 3. Liga to the Bundesliga where I quickly battled for international spots. In the past season I won the league with 33 wins, a single draw and a GD of 105 and was unbeaten in all competitions. Your CWB should be very good offensively as he should be getting a lot of assists (my main CWB was a youth academy winger who I retrained to a CWB as he already had decent enough defensive stats and always gets the most assists out of anyone in my team).