doesn't the klasse kit come with Klasse All in One, Klasse Sealant Glaze, and Souveran?
Are you only going to use the KAIO, then Souveran? If so, then you needn't wait to apply the Souveran. But remember, it is more of a beauty wax and is not very durable. KAIO has some protection, but it is more of a chemical cleaner and base for the real workhorse in the trio, the Klasse Sealant Glaze.
That said, I would not skip the KSG. If durability and looks is what you are after, do it right the first time by putting a coat or two of KSG on top of the KAIO, wait 8 hrs for the sealant to cure, then top it with Souveran.
KSG is a bit finicky to apply. You want to put it on so thin that it looks like windex evaporating on the paint against the light. It won't look like anything is there but it is. If you put it on too thick it is very hard to remove. See my thread below for full tips on application: Winter prep
The wax won't last super long (maybe 2-3 weeks max) especially if the car is not garaged, but you can rest assured that the KSG and KAIO will be there for a long time so maybe once a month, following a wash, you can apply Souveran to maintain that deep wet look.