We use a PumpTec HVLP unit for staining. 12 volt, variable pressure and volume flow. Portable, with an attachment to carry a 5'er.
When just starting out 13 yrs. ago, owned a Binks SuperBee commercial airless. Was a PITA, heavy, and though adjustable, no matter what the tip and pressure, created the "fog of doom" with stain. I'm sure airless are lighter and better designed today, but we'll stay with the HVLP.
Ready Seal is very thin, almost the consistency of water. The real benefit of the PumpTec is adjustable pressure and flow. We can apply a ton of stain in very little time and use it for floors, cedar siding, and balustrades. The most labor saving piece of equipment I own. Pays dividends after a few jobs.