The Lattice deformer lack something I have noticed when trying to use the lattice deformer it doesn´t have an option like in other programs to fit the lattice to an object size. It would be a nice addition to have such option. It would avoid too much guesses. Cinema 4D have this option in the lattice deformer.
There is a request over &quot;Rightclickselect&quot; website for the Blender team to take under consideration for something like this. for now, there are some add-ons like simple lattice that you could check
https://github.com/BenjaminSauder/SimpleLattice