Advice on relief height in simulation photo

Below is a project I’m working on that combines 6 different STL files (24"x24"). I’ve never done this before (combining STLs) so I’m not sure what I might need to avoid.

I’m concerned that the abrupt cut-off of the flowers, for example, that stick up higher than the address block at the bottom might not look good when carved. What do you think about the height differences between the stl files? Other concerns I should note? I’m working in Carveco.