The short answer is "Yes." But try teaspoon measurements as well.
0.2 g Metol is 1/16 tsp. The smallest measure in most sets is 1/8 tsp. 1/8 tsp Metol + 1 tsp ascorbic acid powder will make 1/2 gallon. The PMK B will work. It is a buffer , and IIRC, the measures I gave for borax and NaOH were to emulate metaborate.
If you make a half a gallon and put it in quart bottles, it will keep a while, and even if you throw away what you don't use right away, it is cheap. The most expensive part of D-23 or D-76 is the sulfite, and you may like the ascorbate formula better without sulfite.
Another ploy, since you must mix the D-23 anyway, is to mix a batch with reduced sulfite, use part to try the ascorbate developer, and add more sulfite to he rest when you want D-23.
Lest you be concerned about teaspoon measurements, I reported in "Kitchen Tested Soups", 1973 Petersen's Photographic, experiments that showed that variations in weight of developing agents in developers like D-76 of more than 10% gave little variation in negative contrast or density.