Technical Repairing road rash using Langka system

So I'm in the middle of repairing 25 years of road rash on my old car (avatar). Several years ago I ordered one of the Langka Chip kits so thought I'd give it a try. So far I'm pretty pleased with the results although it's a learning process to not remove too much dabbed on paint, as well as the sheer number of chips makes it slow going. The main component of the kit is their "blob remover" liquid. It works fine but at $20 for 2 oz it's kind of pricey.
Anyone have a suggestion for a substitute for their proprietary remover? The paint on the car is enamel so lacquer thinner ain't the answer.

 

You will just get more on the Back to the Fiftys trip.