I'm thinking of designing a developer that requires you to add Vitamin C (ascorbic acid) separately using a measuring spoon.
Would this be too much extra hassle?

You would do the following:
1. Pour developer into your beaker as usual.
2. Measure out 1/2 or 1 teaspoon of Vitamin C.
3. Stir until dissolved (a couple of minutes).

I discovered that ascorbic acid can be measured consistently (within 5%) using a measuring spoon by first scooping out a heaped spoonful, then compacting it by pressing firmly upward against a flat surface, and then scraping it level. That gives you an accurate packed-and-leveled spoonful.

Adding ascorbic acid separately means you can mix your own ascorbate-based developer and have it last many months instead of just a few weeks. For example, you could mix your own XTOL-clone, and then you would not need to mix 5 litres of XTOL and waste much of it when you can't use it all. But you'd need to do the teaspoon-routine each time you develop. Is it worth the extra effort?

Mark Overton