Well, plenty of people will claim you can't layer carnaubas, period.
Generally, liquids are less likely to layer because they have more solvents.
When I use #16, I find that a second application, after maybe a week, improves the vehicle's appearance. Can't say about the #26, haven't used it in ages.
I think that the #16 will give you the "wetness", whereas #26 would give you more "richness" and "depth".