It looks like the Mosquito should come in on Day 9 limited to the rear fields, and then be fully available on Day 11.
With regard to the 109 availability, the reason I phase them out and limit their availability is because the 190 was the primary fighter on the channel front at that time. For instance look at August of 1942. This is when the Dieppe raid occured, resulting in some of the most intense air combat of the mid war period in the west. At that time the Stabs and Gruppen of JG2 and JG26 were equipped entirely with the Fw190. They each had a Hoehen staffel (10-15 aircraft) equipped with the new Bf109G's, but both units were based in Munich and about to be transferred to Tunisia.
In the spring and summer of 1943 the 109 makes a return to western front action, as II/JG2 and III/JG26 (about 30-40 aircraft for each Gruppe) both convert to the 109G, and the 8th AF bombers start pushing deeper in Europe and encountering the Bf109 equipped gruppen of JG1 and JG11.
As for the types of 109s available, it's based on what was on the books for the active fighter units that were seeing action in the west. Yes there were still a few 109E's an F's around in 43 and 44, but they were assigned to training units. The only "combat" they saw was when some roving US fighters strafed their field and maybe caught some poor student in the pattern. As a rule, the frontline gruppen were being supplied entirely with the latest models, and were trading in their older mounts (which probably went to the schools) for them.
All that being said, if the setup isn't fun to play then it should definitely be tweaked as necessary.
