What a joke they are for something that you are going to wheel and give the clutch a good work out. Adjustment? aint none.
Just a note. Virtually all hydraulic clutch systems are self adjusting at the slave cylinder. They are designed for the t/o bearing to be in contact with the clutch at all times. The slack is taken up by the cylinder itself, much like a hydraulic cam lifter.
As for the internal versus external slaves, there are pluses and minuses to both. Internal cylinders eliminate forks and pivot points, provide even pressure around the t/o bearing, and are shielded against most of the dirt and debris that get driven up against the side of the bellhousing. Their greatest downfall to me is if one goes bad, well, lets just do a clutch while we are in there.......