Optimal position of humidifier cover in relation to the polishing platform. This ensures that mist coming from humidifier will easily reach the platform. Also, being in the front (rather than the back) makes the mist more visible while polishing.
It appears that 35 mins. is the ideal polishing time when using 70% ethyl alcohol. This resulted to good overall surface polishing with no visible layers (except the underside of the model) while fine details are still very sharp. See polished Bulbasaur model for the result.
After moving the humidifier to the front side closer to the polishing chamber, I observed that polishing has become more efficient. Using 70% ethyl alcohol for 45mins seems too much causing the part to be over polished (part in question -- Charmander in Polysmooth Snow White). Will try 30mins next time.
Better polished finish is achieve if part is printed with thicker walls (I'm using Ultimaker Original with wall thickness setting set to 1.6mm). A thicker wall ensures that the infill isn't visible even after polishing the part.
Alcohol, after polishing, seems to leave stains in the walls and floor of the polishing chamber. I wipe the alcohol residue every polishing session but not sure what will be the long-term effect to the Snapware container if if alcohol residue is left to dry without wiping after each polishing session.
Due to the location of the humidifier, the mist is better seen from the back of the chamber. Humidifier should be placed in the front so the mist is more visible all throughout the polishing job.
Among the chamber light colors, yellow seems to be the best light color that makes the mist most visible.
Add preset times to software, e.g., 15mins, 30mins, 45mins, etc.
Add Pause feature. As of 2017-04-06, clicking the button stops the polishing and timer doesn't remember the time elapsed to polish
Add feature to turn on chamber light while in READY mode. Perhaps rotating counter-clockwise cycles through the different light colors. Rotating clockwise while in READY mode enables/disables the sound/beep.
Have USB connector in power panel for routine software updates
Have a "catch basin" structure in the chamber floor to collect the alcohol residue so wiping the walls and floor of the polishing chamber after each session will no longer be needed.