D-23 works perfectly well without the solution B. It is similar to D-76 that way. The extra time in the alkaline solution does increase the low density areas on the film as well as base fog. So if you want to use solution B, you could simply add 9.5 teaspoons of borax to a liter of water for the second bath. What I do is I use white plastic film containers or larger plastic containers or small plastic drinking cups. I measure the amount of powder I need for a given formula, pour it into the container and mark the side of the plastic container with a black marker pen. The you don't have to fuss so much with a scale or multiple spoons full. Just scoop your powders up to the line.
