Best grow lights for bioactive enclosure? Are there any smaller sized tubes?

I have a large enclosure I’m trying to install a couple grow lights. The ceiling of my enclosure has support beams going across so the 8’ ceiling is divided into 4 quadrants of 22”. I can’t find any tubes less than 24” at my local stores. Are there any good brands available that carry tubes that are like 18-20”?

How many tubes would I need for a handful of plants on the ground and another handful in the wall background ?

Edit: something like this is what I’m looking for. Will this work?