To be fair (nothing wrong with a cimex), but i would buy a second hand Commercial Op machine like the Hruby Orbot, and if I couldn't find one used then just buy new, then I could service comm just as well, and also do other type of work to make money, then put the savings into chems (cause you will need them) and pads and Marketing.
And yes I would initially focus on commercial, and then do "both" as time went on. I don't think most guys lay down a good enough base of annual contracts before moving on to residential....and when I say residential, I'm referring to rentals and prop. mgmt. work initially, not Mrs. Piffelton's castle.
The rental market is great to cut your teeth and learn some stuff while making money and developing your spiel, that's a big "should do" in the beginning before putting the time into developing a loyal resi biz.
If you can't make a go of this biz in commercial, you never will in residential.