Remember to apply gloss before and after. And while at it, have you considered a pin wash for the panel lines? Dark like black oils (art or model shop) or enamels (modelling products) so it flows (even more with the gloss) and can be removed (different thinner/solvent than acrylics) until right. It should give it the lines you see where car panels meet, increasing depth sense.
Actually on those models, the detail lines are so thin that doing a proper lining will be a pain for me. Additionally, when seen in real, the panel look pretty well defined whit the actual paint job (or at least, I'm happy with how it looks), so I think I'll stick with the actual state rather than trying to move from good to great and ending to worse. I'm used with the decals job (done quite a bunch of Blood Red Skies squadrons during the last 2 years) but it is always worth the reminder. Yep, same thing here. Nevertheless, this is a great video you shared here. Spoiler: Disclaimer That's a personal opinion here but I'm not fond of people recommending odorless product without noting that just because it doesn't smell it's not necessary harmless (same as 'natural product' not necessary healthier than manufactured ones).
The model should be the one doing the lining, so to speak. Lining more than shadowing (demo video leaves a lot of black in some areas, like above of shoulder pads' bottom trim), or micro shadows if being picky. Apply roughly and clean up until only fine lines remain, that is the reason for not using acrylics. It is not about plain definition, but about the contact effect. "Holes" appear as black matte zones, no light getting out. Look at any car side, doors have black edge, that is what I mean. Spoiler: 4th pic As for "healthy"... follow the labels (but not the California ones, because there H2O is lethal *wink* ). Other way I can see is using fully watersoluble paints, and airbrush / spray varnish once done. There was ModelMates range, but seems gone (at least site is, some shops still have a few products), so artist watercolor seems best option now (never tried, but MM probably was something like that).
I totally know everything you're talking about as I use it for model, but when you go down to a certain scale, the technic is not easy to apply. In this specific case you have to consider that there's already one primer layer, one base layer one wash layer in very thin recesses over which I should apply another layer of glossy varnish. Maybe some very talented people can keep those small details usable AND apply a clean lining over it. Please don't misunderstand my point here. Adding contrast with lining will definitely enhance the final render of the mini, it's just that in this case I won't even try at this point.
In the end, after being taken by study and butterfly syndrome, I nearly finished my shas (edge highlighting.... ) in the spare time I had I started thinking of a colour scheme(and lore) for the PanO minis I have: I decided that they will assume the role of "inquisitors" checking on the other PanO formation by being the bad guys during mock attacks, rapid deployed reinforcement, and "cleaners". For the colour scheme I would go with a dark blue/indigo(as per pano spec ops) main/armour but here I have a problem since I don't know what shade of blue to use (I know CB is affiliated with Vallejo but I only have Citadel paint, so I'll refer to them): should I go with a Macragge Blue or a Kantor Blue? I find the second to be a bit too dark but I fear that the first one would be too close to the PanO "standard": any suggestions? N.B. As per the sectorials'accents I'll go with the following base colour Varuna - sotek green and black Neoterra - mephiston red Svalarheima - black and white Acontecimento ...
I don't have much Citadel paint myself so I can't help to choose but in this thread you'll find several resources that may help you to ease the conversion.
Sorry for the poor quality of the photos(I still have to learn how to use the damn camera) but here there are my unfinished Knights of Santiago What do you think?