single stage vs base coat clear

All depends on how the paint gun is set up, also the quality of paint gun makes a big difference,
When we painted my car my dad had a 200-300 matson spray gun that he has had for 15+years that uses only for clear, that being said spraying single stage is basically the same as spraying clear, at least to me it is

Also needle size and the spray gun head and pressure can make i difference as well

Spraying base coat you go slow
Spraying clear or single stage usually a lot faster as it is wet as soon as you pass over the surface