I really don't see the need to over-complicate this issue.... if all one want is to have developer stock solution last as long as the manufacturer says. It can be done with commonly available "Data Bottles".

In my past experience with D-76, Dektol and XTOL, using commonly available DATA BOTTLE type plastic containers allowed me to keep the working solution for rated duration, at least. The trick is to minimize introduction and repeated introduction of fresh oxygen to the mix. When I used one 1 gallon bottle for D-76 and Dektol, last few "servings" of solutions were considerably dark and weak. Having bottle opened so many times and fresh oxygen getting in dozens of time must have done it in. I think I threw some away back then.

What I do now is this:
Freshly mixed stock solution gets decanted to a series of bottles.
ONE 1/2 gallon data bottle
ONE 1/4 gallon data bottle
ONE or TWO 1/8 gallon data bottle (used for XTOL which comes in 5 liter bag)
Remainder goes to up to FIVE 8 oz bottles of similar materials.

Start using from smaller bottles. Note, each smallest bottle is "one serving" per bottle. Once all small bottles are empty, larger one get decanted into small bottles. This process continues until the largest one get decanted to remaining smaller ones.

This way, re-introduction of oxygen is limited and number of bottles required are minimum. In my experience, they last at least 8 months. I also have an added convenience of one bottle being per serving.

It works for me.

By the way, there are no Data Bottles in 8 oz sizes. I use plastic bottles that are made of the same material as Data Bottles. Picking wrong type of plastic resulted in early degradation so it is important to watch for the right plastic code at bottom.