I have made and used their recipe for powdered soap for several years, and = have had great success with it. (I don't make the liquid version because I= don't like messing with large amounts of boiling water, and don't like car= rying heavy buckets of goop from my kitchen down to the basement.) =20
You can use Fels Naptha bars OR ordinary Ivory Soap bars. I use Ivory, whi= ch is easier to find, significantly less expensive, and far easier and fast= er to grate! For the grating I use my microplane. On "laundry soap day" I= just get out the ingredients, my microplane, a measuring cup, and a great = big old mixing bowl and go at it in the kitchen while NPR is on the radio. = I don't even bother to stir it up very well, because I grate soap, add the= borax and washing soda on top, give it a wee bit of a stir, and then grate= more Ivory and top it with borax and washing soda. I stir every "layer" a = bit, and then make more layers. When I run out of Ivory soap bars, or when = the bowl is getting really full, I'm finished. I store the soap in a large= plastic bucket with a lid, and have a tablespoon on top. As for how much t= o use, I have a top-loading washing machine, and use 1 tablespoon for ordin= ary loads. For extra-dirty loads I use 2 tablespoons.
I'm not a big fan of the Duggers, either, but decided to try their laundry = soap recipe simply because so many commercial laundry soaps have added ingr= edients that make me itch like crazy. This stuff does not. It works very = well, and if you want to watch it, take a tablespoon or two of it in a sand= wich baggie to the laundromat and use it to wash a bedspread in one of the = giant front-loader machines with a window in the door. I find that my laun= dry comes out completely clean, with no odor, and with nothing that makes m= e itch.
If you don't have large plastic buckets with lids handy, go to the bakery a= t the local grocery store and ask to buy a couple of the ones they use and = then usually throw away. My grocery will sell a 5 gallon bucket with lid f= or $1. You can also scrub out the plastic buckets that come with latex pai= nt. You probably would want to avoid plastic buckets that come with lawn c= hemicals, of course. =20
I suggest you give the powdered version a try and see what you think. Make= a small batch as a trial.