Thinner

There are a number of thinners that will work. If they work for butyrate dope, they will work here. Be advised, however, that different thinners have different drying rates. Too fast and there won't be any tooth to bond. Too slow and you can get melt down or take weeks for it to cure before you can sand properly. The Brodak thinner is made to dry quickly but with adequate tooth. It will speed the process of curing and allow you to sand a harder surface much quicker.

Cheaper alternatives are not always better considering the actual amount you will be using for your airplane and the total cost (in dollars and hours) spent.

Use the good stuff for your painting and get some cheap stuff to clean your brush or gun with afterwards.

I essentially do that. I mostly use a brush and clean it with general purpose lacquer thinner...then I give it a second cleaning with Brodak thinner. It does get a little more paint out. Perhaps it is the brand of lacquer thinner I'm using though.

You can use virgin lacquer thinner. Don't use the other stuff for cleaning guns even though it is cheaper. The cheap stuff sells for 25.00 for 5 gallons. The stuff you need sells for 12.00 per gallon.

Remember the finish starts with the first piece of wood cut.