All well and good if the Ruhr actually contains the factories you are interested in.
Bombing the steel works will eventually work but if you are ignoring the aircraft factories that are beyond your self imposed limit it may be a long slog to reduce the German air force defense.
Too much concertation also makes German AA gun location a lot easier. Just send the majority to the Ruhr and the approaches and use the Ruhr as a giant flak trap.
Of course you vary the targets, but the Ruhr is major focus. That the Ruhr is important to German armaments manufacture is demonstrated by what happened historically — the RAF's campaign against it in the first half of 1943 resulted in a stagnation of German armaments production for nine months, as Adam Tooze documents in The Wages of Destruction, citing the German's own records.
The Ruhr could be a linchpin to forcing the Luftwaffe to come up and fight in 1943 in the same way attacks on aircraft production in early 1944 forced the Luftwaffe to engage.
Having both the RAF and the USAAF hitting it day and night in cooperation would also pay dividends which didn't exist historically as the two tended to operate more independently.