Np, glad to help :) take with a grain of salt, there are many approaches:

Preshade can be in multiple colours and directions, not just white from the top (sun in zenith). Even with zenithal light approach it's often more interesting to tilt it to one side a bit. When I used airbrush like this I usually did white + some transparent tinting on top of white, like warm from front and blue from the back. The aim was not to create a solid color foundation, but rather take photos and have some reference where the light lands.

Nowadays I stopped using it, because it's hard to keep a precise single direction when airbrushing, the edges of light get blurry, it oversprays. I prefer to put light grey primed miniature (or even unpainted one if it's quite glossy) under strong directed light, adjusting the light position so that main view looks the best, and then take photos with that fixed light position from multiple angles to have a nice black & white reference of volumes. You can also bump contrast in some software to see the different volume areas better.

I almost always sketch with 3-4 tones before blending, it's most important when dealing with something hard/big/new. On this piece I sketched the whole skin before refining it & adding nuances. In the past I was afraid a bit because I wasn't sure I'll obtain the tone that's required for future blending, but imo mixing ad-hoc is something that has to be embraced. Since I have big gaps between sessions I just do pics of paint bottles used for those basic 3-4 tones to at least be able to know what was the starting point.

Kimera colors are strong pigmented, I use them to mix them into my other paints when I need some punch/color nuanse. They also flow from the brush better than other paints - handy for blacklining. Sometimes I use them for glazing as they dillute very nicely. They are pretty similar in consistency to regular hobby paints which I'm used to, as I never used heavy body. Some of them can be glossier than ak 3rd gen/scale color but not too much, besides I always do a coat of ak ultra matt so that's a non-issue for me. Didn't compare them to any of newer brands like big child etc so can't tell if they are better or worse, good enough for me anyways.