I know u-boats carried HE ( high explosive ) , AP ( armor piercing ) , star shell and incendiary rounds for the 105mm guns. For the 20mm guns they used HE tracer and HE incindiary tracer rounds.Sometime around June 1943 a new 20mm round was developed and also used on u-boats called MINENGESCHOSS or mine shell. The 37mm used HE , HE tracer and HE incindiary tracer rounds. The 105 mm gun did not have a fuse setter mounted on it so if a round did have a time fuse it would have to be set manually by one of the crewmen before loading it into the breach of the gun. I do not know for sure on the 105 ammo but I do know that the 88 mm star shells did use the S/33 or S/60 time fuse.
In general a Type IX carried 150 rounds of 105 mm , 2575 rounds of 37 mm and 8100 rounds of 20 mm when using 2 twin 20 mm guns . This may change with the mission and the boat, inside the control room of the U-853 sunk off of Block Island RI the crewmen welded 4 strips of angle iron to the floor standing vertical and in a square pattern .This was done inorder to stack more 20mm ammo clips near the ladder to the bridge,each angle iron fit up against a corner of the ammo clip.I guess they felt that they needed more AA ammo so this is an example of more ammo being carried than would be listed in most U-boat books. I have been diving this wreck for 20 years now and thats how I know this crew modification is there.
Both the u-boat 88 mm and 105 mm guns are not related to their land gun counterparts, nor is their ammo so I do not think looking in a general book on German field guns will give you a correct answere on fuses used on German U-boats.
At one time a manifest did exist on each boat . This was needed inorder to receive the boats stores of fuel,food,spare parts and weapons like torpedos and gun ammo. But as the U-boat bases became surrounded most of the documents were destroyed before they fell to the allies, after the capitulation this stuff was of no real value to them and what was left was thrown out.