Thats about my limit above the soil line as well , however i will be upgrading the tent at
@MamaMouse ‘s from a 2’x2’x4’ to a 3’x3’x6’ tent. Should be able to pull substantially more with over twice the space and two more feet in height. Ive been in 2’x2’x4’ tents for so long and have adapted my growing styles to those areas, i usually have a plan for taller plants, scrog or lst etc.