Some suggestions for Western front air battles described from both sides:
From November 1940 to June 1941, Foreman's books "Battle of Britain: the forgotten months" and "1941: the turning point" (two volumes for the latter) describe with great details all air battles seen from both sides. Most actions are squadron-sized.
JG 26 history by Caldwell gives daily details about JG 26 and usually identifies the opponents of this unit, even if most is described from the German view. But you can complete it by using Allied sources to have a complete one.
For the Western campaign, Arnaud Gillet's books (in French) about French victories (3 books covering 10 May to 25 June) and RAF victories (so far, 2 books covering 10 May to 4 June) describe most air battles with details from both sides. Attempts are made to identify opponents of the Allied pilots for each claim.
Regarding late years of the war, Shores "2nd Tactical Force" series (3 books) is IMOO too much centered about air battles (opposed to the effects on the ground of strafing, bombing and so on), but will so perfectly suit you. In many cases German opponents are identified. In all cases Allied claims and losses are detailled.
The book “Air War Italy 1944-45: the Axis Air Forces from the Liberation of Rome to the Surrender”, by Nick Beale, Ferndinando d'Amico and Gabriele Valentini. ISBN 1-85310-252-0 describes all Luftwaffe and ANR activity in Italy from 1 June 1944 to the end of war, and every battle with details from both sides.
By the way Nick Beale has a website (http://www.ghostbombers.com/) where you can find description of several battles (check the sections about I/JG 2 and Jadggruppe 200 among others).
There are also books describing one precise day (examples: operation Bodenplatte, 12 May 1944, 14 October 1943, 2 March 1945) with many details.
Regarding the availability of German records, it has nothing do you with the "transient lifestyle" of most units. At the end of the war the German authorities ordered to destroy all records and this was done on a very large scale. So all German side of the actions has to be built from fragmentary or secondary sources. Even with these disadvantages 66 years of historical research are allowing now to have have access to many things.
But you will never see a book on Luftwaffe like the "First team" series in the Pacific, where for some battles the author is able to give the name of the pilot of every aircraft of both sides !!!!
To finish here is an extract of Fighters over the desert (date is 16 July 1942, the last action of the day):
"
In the evening, twelve Tomahawks of 5 SAAF Squadron patrolled over the Alamein area, meeting Ju 87s escorted by nine Bf 109s of II/JG 27 and six of III/JG 53. Lt. Bidwell and 2/Lt. Kearns each claimed to have probably destroyed a Ju 87, Capt. Armstrong and 2/Lt. Smith each claiming a Bf 109 probable. Lt. Sommerville’s aircraft was badly damaged by Lt. Schroer of II Gruppe, who claimed a victory. III/JG 53 reported that one Ju 87 force-landed."
Notice that the number of Ju 87s is not given in this example
Continuing with the first actions of 17 July:
"Early on 17th twelve Spitfires of 145 Squadron provided top cover to the Hurricanes of 73 and 7 SAAF Squadrons on patrol. They were jumped at 0737 hours by eight Bf 109s of II./JG 27 on a ’Freie Jagd’, Oblt. Sinner shooting down Sgt. Rostant of 145 Squadron, who baled out with a wounded arm. At 1115 hours four Spitfires of this unit again took off to provide top cover to fighter-bombers, this time Kittyhawks, seven from 3 RAAF Squadron bombing in the Dir el Abyad area. Between Alamein and II Amyid the formation was attacked by eight Bf 109s of III/JG 53 on a ’Freie Jagd’, who claimed one Spitfire and one Kittyhawk. PO Weber of 145 baled out, but broke his arm, and Sgt. Stevens of 3 RAAF received severe damage to his aircraft."
Best regards