Gonna be just a little cynical here,..but in a positive,..for your own good kinda way,..Ha,Ha,..
You should be starting with at least 4-5 GPM machine. With 8 GPM being ideal for many. The difference between 2.7 GPM and 4-5 doesn't do the performance curve justice.
Rinsing and shooting distance,..like the peak of a two story is where you'll see the difference once you do go more GPM.
I think the "tools" part of business is the easy part, that way you can put more effort into other aspects of the job. Like learning techniques, cleaners etc...
Also, you'll want a surface cleaner, and 2.7 isn't gonna run one. When flat surface cleaning, more GPM not only cleans better,..but also flows dirt away better.
Trying not to be mean,..just trying to do you a favor.
**Doesn't mean you can't do the work,..but it's gonna be alot more work.
Jeff