I buy a lot of chems in 25 ltrs and even buying like that white spirit is about £1 per ltr. How that can be cheaper than more effective professional chemicals I do not know.
I would suggest some training, as said being non ionic the spirit will not disperse within water. The same problem is encountered rinsing with water.
Peter
www.carpetcleanercardiff.com
Over the years I have done training with Extracta, Alltec, Prochem & NCCA

Just finished cleaning my own hsl & lounge/diner using said product, Enrituals Passion Liquid Detergent plus the softener that goes with it. I used 10 litres of hot water mixed with 10 cupful of detergent & the same with the softener, all in all it cost me £1.00.
Sprayed on, dwelled, rinsed off. The quality of the clean is far better than I was achieving using F90 or Craftex Premium (that was 2 years ago), and the lovely smell lingers around the house for days after.
I can't fault using these products at all. I am certainly not on a wind up, I seriously use these products or similar.
To you they may seem unethical or unprofessional, but to me I use what works the best.
Don't knock it till you try it. Why not do a test on a rug or spare bit of carpet and you'll realise how effortless the cleaning will become.
Also, it probably took 30 years of technology developing the liquid detergents too, and they are designed to clean/wash nylon and wool fabrics regardless whether they are on your clothes or in your carpets!!