Thiocarbamide and 1-shot usage

I usually mix 100ml of stock solutions because they can sit for quite some time and I use very small quantities. The activator can form a precipitate over time (even though I mix with distilled water) and I want to be sure it’s at full effectiveness.

I have been redeveloping 8x10 inch prints 1-shot using very small quantities of toning solution. 6ml total of a combination of toner & activator in about 60ml of water fully redevelops at least 1 print. For example, 3ml toner + 3ml activator + 60ml water. With that little solution of course you would use a flat-bottomed tray.

I just noticed that in his toning book, Tim Rudman says to dilute the thiocarbamide solution 1:9 before use, which I have never done, and have not seen written anywhere else. And in the Darkroom Cookbook the formula indicates half strength thiocarbamide stock solution. I use 1:10 weight to volume for stock solutions.

Anyone see any issues with what I’m doing?!

In assume this is about sepia toning.

With thiourea sepia toning, the ratio between the thiourea and the activator (typically sodium hydroxide) determines the image tone. It can be set on a continuum from yellow to purple brown tones this way.

I've made a small illustrated guide for this here: https://tinker.koraks.nl/photography/shades-of-brown-controlling-sepia-toning-hue/
It includes the mixing ratios you need to replicate this.