That 41-2 restriction was due mostly to having to deliberately place the sweeps at a tactical disdavantage to try and get the Luftwaffe to come up. The individual operational plans of course varied greatly from operation to operation, but if I were to generalise, it gnerally took the form of small groups of bobers, under close escort of most fighters in the group, followed by an "ambush group, either further behind, or in front, trying to trap and gain advantage over thye German interecptors. Sometimes it worked, often it did not, and IMO as time progressed, the germans got wise to RAF tricks and ruses.
In the first half of 1941, according to Foreman, the exchange rate wasnt too badly against the RAF In the second half it swung quite badly against the RAF.