Thinning small amounts of paint

That is one method to accurately mix paint/thinner.

I prefer to mix in the AB cup, use a pipette and have never had an issue either, cost .30cents for each pipette that last 6-8 months each.

I dont like mixing in a cup, as I waste the cup and paint.

I use these disposable plast cups with a lid.

https://www.amazon.com/gp/product/B06WGMS4BM/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

and pipettes for thinner like damouav.

Pour in the paint, thin then close the cap and shake to mix.  Worst part is popping open the lid without getting covered in paint ;)  With my Passche  H, a full one of these cups fills about 3/4 of the suction feed cup.

Those sensitive scales also come in handy for weighing out noseweight for tri-gear airplanes (when kit mfgs do indicate how much weight it takes).

A very unusual way to measure thinner to paint ratio. Nah.... I prefer using pipettes. Not worth spending $10 for a digital scale. Besides I can acquire quite a few cheap plastic pipettes practically for free.

Usually just eyeball my mixes in a gravity feed bottle, stir well and pour into the gravity feed cup.  Not much waste, and don't have an issue with thicker paint in the feed section of the NEO when I first pull the trigger.

But do have one of those scales for my gold mining activites.  I like to know how much $ I lost in my recovery efforts.

Where I could see that thing being pretty useful is mixing colors.

I kind of wing it with thinner.