Kitbashing ​

Open Stand-In Outliner Window / Stand-In Outliner.

Select Static meshes you want to make a kit from.

Select Create in the Stand-In Outliner.

Pick Near Pipeline.

Build Stand-In

Save to package.

Select path.

Repeat for another kit

Bash kits together to form new kits.

Add casters. Optional Material Merge

Adjust Output Texture Resolution. Optional Material Merge