I second rhg3's recommendation! Reading Neil Antin's Precision Aqueous Cleaning of Vinyl Records-3rd Edition - The Vinyl Press is not an easy read but well worth the time!
I have not included alcohol, thus far, in any of my record cleaning solutions. However, using the correct amount or proportion of the right type of alcohol in a proper record cleaning solution, using the proper cleaning technique, is not, I believe, harmful to PVC records. Based upon my understanding of what I've read and researched on the topic, thus far, I also believe that a little alcohol might, indeed, be necessary to clean extremely soiled records. Many pre-made solutions include some amount of alcohol and surfactant.
Last I read a piece written by The Audiophile Man, Paul Rigby, I believe he is using the Degritter US machine now. My understanding is that the HumminGuru is nice but limited by its power (i.e. wattage and cleaning frequency). Regardless, I am currently using a similar over-the-counter US machine in my cleaning regimen incorporating the use of a Disco Anti-Stat and have done an A/B cleaning comparison with the original Degritter. The audio quality results rendered on the 3 or 4 albums that I used were, effectively, the same. Despite this, I am still considering the purchase of the newest Degritter machine because it is so much more convenient (i.e. considerably less labor intensive) than my current lash-up regimen. Maybe it'll be a Christmas present to myself this year.

