I have my 13" Zipper jr setup with 5x 02 jets =10flow and my PCTI wand 6x 02 jets= 12flow... 20hp Honda motor, 45 blower, #4 Little Giant Heater... I've put 03 jets on my Zipper jr for 15 flow... Worked good but the filling of the waste tank sucked with I'd have 100sf left... I dropped it back down and the only difference I really see is how much thicker the waste water is than the 15flow... 1.5jets clog too easily for me...
I agree on the jets clogging.
I had to redo a job yesterday, because, Originally, the carpet needed to be thrown away from it being so trashed...But I tried my best. I was so disappointed in how it came out, I told the customer that I'll come the next day after it dries and try it again.
The first time I did it...I used my 7.5flow 5jet wand. The second time, I used my 4jet 8flow wand, and it flushed it better. The water was just as nasty as the first time I cleaned it, and it was only .5 flow more. That tells me that a 10flow with #2 jets will do a job 100times better than a 7.5flow #1.5 jets any day.
I'm gonna swap my jets out this weekend and make my mach15 a 10flow wand