Hi Michael - Since most of the triggers are layer triggers, your best move is to copy/duplicate the layer and then update/modify on the new layer.
One workflow I found was to create the initial slide layers at the beginning of the project. They're blank layers but they enabled me to set up the base layer tabs and add then copy the first round of triggers (pause timeline, move group, show layer if...). That helped me focus on specific triggers as I copied and pasted.
The workflow with this type of interaction isn't as clear cut as it is with other interactions since we're copying all objects to each layer. That's really where this becomes a custom interaction that isn't easily updated with different numbers of tabs.
To your point about having the whole solution in your head is really the case here. If I were going to create a 4-tab version, I would start over by duplicating the base layer and rebuild the slide layers from scratch. I feel that's faster than trying to fiddle with the positioning of objects on every layer.
Storyline's new motion path features make this super easy to build. It would have taken much longer to get right in previous versions.