I was tired of looking for what I wanted, a base XXI in 1939. So, here's what I did, I changed the availability date for the xxi, changed the availability of the base equipment, modified a little bit the avail date of the 'optionnal' qeuipment.
So what I get is the base XXI with base torpedoes in 1939 and when available, I equip my boat with future tech stuff. After finishing a patrol from 1939 to 1945 in a IIA and IID, I needed something different. I'm in 1940, no upgrades yet but still I rule the seas, except the kanal. I even entered Scapa Flow, just for fun, sank the tanker and aimed for the troop transport, to no avail... damn nets. Amaisaingly, I got away with it with no scratches

. I can send my files if you guys are interested (Only got the Flotilla 1 modified for it; I kinda like the Kiel Canal).