Research the German aircraft occupying Bordeaux/Merignac airfield, as this was one that hosted various maritime strike and maritime reconnaiscance units.
Chiefly, Ju.88 H’s were used, as were a few He.111 H2’s. Later, He.177 Greiffs are employed. Ocassionallly an FW. 200 appears there also.
For the Ju.88 and He.111 there were extra fuel tanks added in the fuselages, which is why the Ju.88 H series is longer than its’ D series parent by some 10 to 12 feet.
Most maritime strike aircraft carried a bombload of less than 2500 lb on short to medium range missions, so one can safely assume that only up to say 1200 lb would be carried on extended range missions.
Engine modifications were relatively few, unless discussing the Greiff.
However, they would have been tuned for medium to low altitude performance, as opposed to high altitude (say 30000 feet).
Hope the info above helps.
Regards, Uyraell.