Just installed a 24k BTU Pioneer mini split in my garage. Takes some time and effort, but it's doable if you're handy. I don't have experience with a dual head unit.
You will need some specialty tools:
Cut, debur, and flare copper tubing (get the Yellow Jacket eccentric)
Vacuum pump
Micron gauge (recommended)
Lineset bender kit (BendAid)
Specialty torque wrench (or crows foot) for flare nuts
Measure everything multiple times before making any critical cuts or holes. The included cardboard template for mounting the inside unit was wrong, but luckily I caught the error.
It works exceptionally well and is very quiet, both inside and outside.
Benjamin Sahlstrom has some excellent installation videos:
https://www.youtube.com/@BenjaminSahlstrom/videos